update scala version in scripts

Update scala3-library to 3.6.2

.git-blame-ignore-revs

@@ -0,0 +1,5 @@
+# Scala Steward: Reformat with sbt-java-formatter 0.8.0
+57ce691a00babb03e0cae03a26fe56d63fc609af
+
+# Scala Steward: Reformat with scalafmt 3.6.1
+f2b19baca828a4d88b46bc009aef6d7115e63924

.github/scala-steward.conf

@@ -0,0 +1,3 @@
+# If true, Scala Steward will sign off all commits (e.g. `git --signoff`).
+# Default: false
+signoffCommits = true

.github/workflows/ci.yml

@@ -16,6 +16,7 @@ jobs:
       uses: actions/setup-java@v1
       with:
         java-version: 1.11
+    - uses: sbt/setup-sbt@v1
     - name: Run tests
       run: sbt test assembly
     - name: Run linter

.github/workflows/docker-latest.yml

@@ -54,6 +54,10 @@ jobs:
           push: ${{ github.event_name != 'pull_request' }}
           tags: ${{ steps.meta.outputs.tags }}
           labels: ${{ steps.meta.outputs.labels }}
+          platforms: |
+            linux/amd64
+            linux/arm64
+            linux/arm/v7
 
       - name: Image digest
         run: echo ${{ steps.docker_build.outputs.digest }}

.scalafmt.conf

@@ -1,3 +1,3 @@
-version="3.4.3" 
+version="3.8.3" 
 maxColumn = 120
 runner.dialect = scala3

Dockerfile

@@ -1,9 +1,10 @@
-FROM adoptopenjdk/openjdk16:alpine AS base-builder
+FROM eclipse-temurin:17-jre-jammy AS base-builder
-ARG SBT_VERSION=1.3.13
+ARG SBT_VERSION=1.7.1
-RUN apk add --no-cache bash
 ENV JAVA_HOME="/usr/lib/jvm/default-jvm/"
 ENV PATH=$PATH:${JAVA_HOME}/bin
 RUN \
+        apt update && \
+        apt install -y wget && \
 	wget -O sbt-$SBT_VERSION.tgz https://github.com/sbt/sbt/releases/download/v$SBT_VERSION/sbt-$SBT_VERSION.tgz && \
         tar -xzvf sbt-$SBT_VERSION.tgz && \
         rm sbt-$SBT_VERSION.tgz
@@ -22,15 +23,15 @@ FROM sbt-builder as builder
 COPY src/ src/
 RUN sbt assembly
 
-FROM adoptopenjdk/openjdk16:alpine-jre  AS base-core
+FROM eclipse-temurin:17-jre-jammy  AS base-core
 ENV JAVA_HOME="/usr/lib/jvm/default-jvm/"
-RUN apk add --update ttf-dejavu
+RUN apt update && apt install -y fonts-dejavu
 ENV PATH=$PATH:${JAVA_HOME}/bin
 
 
 FROM base-core
 WORKDIR /lc-core
-COPY --from=builder /build/target/scala-2.13/LibreCaptcha.jar .
+COPY --from=builder /build/target/scala-3.6.2/LibreCaptcha.jar .
 RUN mkdir data/
 
 EXPOSE 8888

README.md

@@ -47,18 +47,25 @@ docker-compose up
 Using `docker`:
 
 ```
-docker run -v lcdata:/lc-core/data librecaptcha/lc-core:1.1.0-stable
+docker run -p=8888:8888 -v ./lcdata:/lc-core/data librecaptcha/lc-core:2.0
 ```
 
 A default `config.json` is automatically created in the mounted volume.
 
+The above commands should work with `podman` as well, if docker.io registry is pre-configured. Otherwise,
+you can manually specify the repository like so:
+
+```
+podman run -p=8888:8888 -v ./lcdata:/lc-core/data docker.io/librecaptcha/lc-core:2.0
+```
+
 ## Quick test
 Open [localhost:8888/demo/index.html](http://localhost:8888/demo/index.html) in browser.
 
 Alternatively, on the command line, try:
 
 ```
-> $ curl -d '{"media":"image/png","level":"easy","input_type":"text"}' localhost:8888/v1/captcha
+> $ curl -d '{"media":"image/png","level":"easy","input_type":"text","size":"350x100"}' localhost:8888/v2/captcha
 {"id":"3bf928ce-a1e7-4616-b34f-8252d777855d"}
 
 > $ curl "localhost:8888/v1/media?id=3bf928ce-a1e7-4616-b34f-8252d777855d" -o sample.png
@@ -139,10 +146,10 @@ The service can be accessed using a simple HTTP API.
         - image/png
         - image/gif
         - (More to come)
-    - `size`: `Map` -
+    - `size`: String -
-      The dimensions of a captcha (Optional). It needs two more fields nested in this parameter
+      The dimensions of a captcha. It needs to be a string in the format `"widthxheight"` in pixels, and will be matched
-       - `height`: `Int`
+      with the `allowedSizes` config setting. Example: `size: "450x200"` which requests an image of width 450 and height
-       - `width`: `Int`
+      200 pixels.
 
 - Returns:
     - `id`: `String` - The uuid of the captcha generated
@@ -173,9 +180,9 @@ The service can be accessed using a simple HTTP API.
 In javascript:
 
 ```js
-const resp = await fetch("/v1/captcha", {
+const resp = await fetch("/v2/captcha", {
     method: 'POST',
-   body: JSON.stringify({level: "easy", media: "image/png", "input_type" : "text"})
+    body: JSON.stringify({level: "easy", media: "image/png", "input_type" : "text", size: "350x100"})
 })
 
 const respJson = await resp.json();
@@ -193,7 +200,7 @@ if (resp.ok) {
 
 
 // When user submits an answer it can be sent to the server for verification thusly:
-const resp = await fetch("/v1/answer", {
+const resp = await fetch("/v2/answer", {
     method: 'POST',
     body: JSON.stringify({id: captchaId, answer: "user input"})
 });

Runner.Dockerfile

@@ -1,12 +1,12 @@
-FROM adoptopenjdk/openjdk16:alpine-jre  AS base-core
+FROM eclipse-temurin:17-jre-jammy  AS base-core
 ENV JAVA_HOME="/usr/lib/jvm/default-jvm/"
-RUN apk add --update ttf-dejavu
+RUN apt update && apt install -y fonts-dejavu
 ENV PATH=$PATH:${JAVA_HOME}/bin
 
 
 FROM base-core
 RUN mkdir /lc-core
-COPY target/scala-3.1.1/LibreCaptcha.jar /lc-core
+COPY target/scala-3.6.2/LibreCaptcha.jar /lc-core
 WORKDIR /lc-core
 RUN mkdir data/
 

build.sbt

@@ -2,8 +2,8 @@ lazy val root = (project in file(".")).settings(
   inThisBuild(
     List(
       organization := "com.example",
-      scalaVersion := "3.1.1",
+      scalaVersion := "3.6.2",
-      version := "0.1.0-SNAPSHOT",
+      version := "0.2.1-snapshot",
       semanticdbEnabled := true,
       semanticdbVersion := scalafixSemanticdb.revision
 
@@ -12,9 +12,9 @@ lazy val root = (project in file(".")).settings(
     )
   ),
   name := "LibreCaptcha",
-  libraryDependencies += "com.sksamuel.scrimage" % "scrimage-core" % "4.0.30",
+  libraryDependencies += "com.sksamuel.scrimage" % "scrimage-core" % "4.3.0",
-  libraryDependencies += "com.sksamuel.scrimage" % "scrimage-filters" % "4.0.30",
+  libraryDependencies += "com.sksamuel.scrimage" % "scrimage-filters" % "4.3.0",
-  libraryDependencies += "org.json4s" %% "json4s-jackson" % "4.0.4"
+  libraryDependencies += "org.json4s" %% "json4s-jackson" % "4.0.7"
 )
 
 Compile / unmanagedResourceDirectories += { baseDirectory.value / "lib" }

docker-compose.yml

@@ -3,7 +3,9 @@ version: "3.6"
 services:
   lc-core:
     container_name: "libre-captcha"
-    image: librecaptcha/lc-core:1.0.0-stable
+    image: librecaptcha/lc-core:latest
+    # Comment "image" & uncomment "build" if you intend to build from source
+    #build: .
     volumes: 
       - "./docker-data:/lc-core/data"
     ports: 

project/build.properties

@@ -1 +1 @@
-sbt.version=1.6.2
+sbt.version=1.10.6

project/plugins.sbt

@@ -1,4 +1,4 @@
-addSbtPlugin("ch.epfl.scala" % "sbt-scalafix" % "0.9.34")
+addSbtPlugin("ch.epfl.scala" % "sbt-scalafix" % "0.13.0")
-addSbtPlugin("org.scalameta" % "sbt-scalafmt" % "2.4.6")
+addSbtPlugin("org.scalameta" % "sbt-scalafmt" % "2.5.2")
-addSbtPlugin("com.lightbend.sbt" % "sbt-java-formatter" % "0.7.0")
+addSbtPlugin("com.lightbend.sbt" % "sbt-java-formatter" % "0.8.0")
-addSbtPlugin("com.eed3si9n" % "sbt-assembly" % "1.2.0")
+addSbtPlugin("com.eed3si9n" % "sbt-assembly" % "2.3.0")

src/main/java/lc/captchas/FontFunCaptcha.java

@@ -5,12 +5,12 @@ import java.awt.image.BufferedImage;
 import java.io.ByteArrayOutputStream;
 import java.io.File;
 import java.io.FilenameFilter;
-import java.util.Map;
 import java.util.List;
+import java.util.Map;
 import lc.captchas.interfaces.Challenge;
 import lc.captchas.interfaces.ChallengeProvider;
-import lc.misc.PngImageWriter;
 import lc.misc.HelperFunctions;
+import lc.misc.PngImageWriter;
 
 public class FontFunCaptcha implements ChallengeProvider {
 
@@ -58,9 +58,10 @@ public class FontFunCaptcha implements ChallengeProvider {
     return null;
   }
 
-  private byte[] fontFun(String captchaText, String level, String path) {
+  private byte[] fontFun(
+      final int width, final int height, String captchaText, String level, String path) {
     String[] colors = {"#f68787", "#f8a978", "#f1eb9a", "#a4f6a5"};
-    BufferedImage img = new BufferedImage(350, 100, BufferedImage.TYPE_INT_RGB);
+    BufferedImage img = new BufferedImage(width, height, BufferedImage.TYPE_INT_RGB);
     Graphics2D graphics2D = img.createGraphics();
     for (int i = 0; i < captchaText.length(); i++) {
       Font font = loadCustomFont(level, path);
@@ -81,10 +82,14 @@ public class FontFunCaptcha implements ChallengeProvider {
     return baos.toByteArray();
   }
 
-  public Challenge returnChallenge() {
+  public Challenge returnChallenge(String level, String size) {
     String secret = HelperFunctions.randomString(7);
+    final int[] size2D = HelperFunctions.parseSize2D(size);
+    final int width = size2D[0];
+    final int height = size2D[1];
     String path = "./lib/fonts/";
-    return new Challenge(fontFun(secret, "medium", path), "image/png", secret.toLowerCase());
+    return new Challenge(
+        fontFun(width, height, secret, "medium", path), "image/png", secret.toLowerCase());
   }
 
   public boolean checkAnswer(String secret, String answer) {

src/main/java/lc/captchas/PoppingCharactersCaptcha.java

@@ -1,51 +1,51 @@
 package lc.captchas;
 
-import java.awt.Font;
-import java.awt.RenderingHints;
 import java.awt.Color;
+import java.awt.Font;
 import java.awt.Graphics2D;
+import java.awt.RenderingHints;
 import java.awt.image.BufferedImage;
+import java.io.ByteArrayOutputStream;
 import java.io.IOException;
+import java.util.List;
 import java.util.Map;
 import java.util.function.Consumer;
 import java.util.stream.IntStream;
-import java.util.LinkedList;
-import java.util.List;
-
 import javax.imageio.stream.MemoryCacheImageOutputStream;
-import java.io.ByteArrayOutputStream;
 import lc.captchas.interfaces.Challenge;
 import lc.captchas.interfaces.ChallengeProvider;
-import lc.misc.HelperFunctions;
 import lc.misc.GifSequenceWriter;
+import lc.misc.HelperFunctions;
 
 public class PoppingCharactersCaptcha implements ChallengeProvider {
-  private final Font font = new Font("Arial", Font.ROMAN_BASELINE, 48);
-  private final int width = 250;
-  private final int height = 100;
 
-  private Integer[] computeOffsets(final String text) {
+  private int[] computeOffsets(
+      final Font font, final int width, final int height, final String text) {
     final var img = new BufferedImage(width, height, BufferedImage.TYPE_INT_RGB);
     final var graphics2D = img.createGraphics();
     final var frc = graphics2D.getFontRenderContext();
-    final var advances = new LinkedList<Integer>();
+    final var advances = new int[text.length() + 1];
     final var spacing = font.getStringBounds(" ", frc).getWidth() / 3;
     var currX = 0;
     for (int i = 0; i < text.length(); i++) {
       final var c = text.charAt(i);
-      advances.add(currX);
+      advances[i] = currX;
       currX += font.getStringBounds(String.valueOf(c), frc).getWidth();
       currX += spacing;
-    };
+    }
+    ;
+    advances[text.length()] = currX;
     graphics2D.dispose();
-    return advances.toArray(new Integer[]{});
+    return advances;
   }
 
-  private BufferedImage makeImage(final Consumer<Graphics2D> f) {
+  private BufferedImage makeImage(
+      final Font font, final int width, final int height, final Consumer<Graphics2D> f) {
     final var img = new BufferedImage(width, height, BufferedImage.TYPE_INT_RGB);
     final var graphics2D = img.createGraphics();
     graphics2D.setRenderingHint(RenderingHints.KEY_ANTIALIASING, RenderingHints.VALUE_ANTIALIAS_ON);
-    graphics2D.setRenderingHint(RenderingHints.KEY_TEXT_ANTIALIASING, RenderingHints.VALUE_TEXT_ANTIALIAS_ON);
+    graphics2D.setRenderingHint(
+        RenderingHints.KEY_TEXT_ANTIALIASING, RenderingHints.VALUE_TEXT_ANTIALIAS_ON);
     graphics2D.setFont(font);
     f.accept(graphics2D);
     graphics2D.dispose();
@@ -56,23 +56,42 @@ public class PoppingCharactersCaptcha implements ChallengeProvider {
     return HelperFunctions.randomNumber(-2, +2);
   }
 
-  private byte[] gifCaptcha(final String text) {
+  private byte[] gifCaptcha(final int width, final int height, final String text) {
     try {
+      final var fontHeight = (int) (height * 0.5);
+      final Font font = new Font("Arial", Font.ROMAN_BASELINE, fontHeight);
       final var byteArrayOutputStream = new ByteArrayOutputStream();
       final var output = new MemoryCacheImageOutputStream(byteArrayOutputStream);
       final var writer = new GifSequenceWriter(output, 1, 900, true);
-      final var advances = computeOffsets(text);
+      final var advances = computeOffsets(font, width, height, text);
+      final var expectedWidth = advances[advances.length - 1];
+      final var scale = width / (float) expectedWidth;
       final var prevColor = Color.getHSBColor(0f, 0f, 0.1f);
-      IntStream.range(0, text.length()).forEach(i -> {
+      IntStream.range(0, text.length())
-        final var color = Color.getHSBColor(HelperFunctions.randomNumber(0, 100)/100.0f, 0.6f, 1.0f);
+          .forEach(
-        final var nextImage = makeImage((g) -> {
+              i -> {
+                final var color =
+                    Color.getHSBColor(HelperFunctions.randomNumber(0, 100) / 100.0f, 0.6f, 1.0f);
+                final var nextImage =
+                    makeImage(
+                        font,
+                        width,
+                        height,
+                        (g) -> {
+                          g.scale(scale, 1);
                           if (i > 0) {
                             final var prevI = (i - 1) % text.length();
                             g.setColor(prevColor);
-            g.drawString(String.valueOf(text.charAt(prevI)), advances[prevI] + jitter(), 45 + jitter());
+                            g.drawString(
+                                String.valueOf(text.charAt(prevI)),
+                                advances[prevI] + jitter(),
+                                fontHeight * 1.1f + jitter());
                           }
                           g.setColor(color);
-          g.drawString(String.valueOf(text.charAt(i)), advances[i] + jitter(), 45 + jitter());
+                          g.drawString(
+                              String.valueOf(text.charAt(i)),
+                              advances[i] + jitter(),
+                              fontHeight * 1.1f + jitter());
                         });
                 try {
                   writer.writeToSequence(nextImage);
@@ -100,9 +119,12 @@ public class PoppingCharactersCaptcha implements ChallengeProvider {
         "supportedInputType", List.of("text"));
   }
 
-  public Challenge returnChallenge() {
+  public Challenge returnChallenge(String level, String size) {
     final var secret = HelperFunctions.randomString(6);
-    return new Challenge(gifCaptcha(secret), "image/gif", secret.toLowerCase());
+    final int[] size2D = HelperFunctions.parseSize2D(size);
+    final int width = size2D[0];
+    final int height = size2D[1];
+    return new Challenge(gifCaptcha(width, height, secret), "image/gif", secret.toLowerCase());
   }
 
   public boolean checkAnswer(String secret, String answer) {

src/main/java/lc/captchas/ShadowTextCaptcha.java

@@ -1,21 +1,18 @@
 package lc.captchas;
 
-import java.awt.Graphics2D;
-import java.awt.RenderingHints;
 import java.awt.Color;
 import java.awt.Font;
-import java.awt.font.TextLayout;
+import java.awt.Graphics2D;
 import java.awt.image.BufferedImage;
 import java.awt.image.ConvolveOp;
 import java.awt.image.Kernel;
 import java.io.ByteArrayOutputStream;
-import java.util.Map;
 import java.util.List;
-
+import java.util.Map;
-import lc.misc.HelperFunctions;
-import lc.misc.PngImageWriter;
 import lc.captchas.interfaces.Challenge;
 import lc.captchas.interfaces.ChallengeProvider;
+import lc.misc.HelperFunctions;
+import lc.misc.PngImageWriter;
 
 public class ShadowTextCaptcha implements ChallengeProvider {
 
@@ -38,32 +35,43 @@ public class ShadowTextCaptcha implements ChallengeProvider {
     return answer.toLowerCase().equals(secret);
   }
 
-  private byte[] shadowText(String text) {
+  private float[] makeKernel(int size) {
-    BufferedImage img = new BufferedImage(350, 100, BufferedImage.TYPE_INT_RGB);
+    final int N = size * size;
-    Font font = new Font("Arial", Font.ROMAN_BASELINE, 48);
+    final float weight = 1.0f / (N);
-    Graphics2D graphics2D = img.createGraphics();
+    final float[] kernel = new float[N];
-    graphics2D.setRenderingHint(RenderingHints.KEY_ANTIALIASING, RenderingHints.VALUE_ANTIALIAS_ON);
+    java.util.Arrays.fill(kernel, weight);
-    graphics2D.setRenderingHint(
+    return kernel;
-        RenderingHints.KEY_TEXT_ANTIALIASING, RenderingHints.VALUE_TEXT_ANTIALIAS_ON);
+  };
 
-    TextLayout textLayout = new TextLayout(text, font, graphics2D.getFontRenderContext());
+  private byte[] shadowText(final int width, final int height, String text) {
+    BufferedImage img = new BufferedImage(width, height, BufferedImage.TYPE_INT_RGB);
+    final int fontHeight = (int) (height * 0.5f);
+    Font font = new Font("Arial", Font.PLAIN, fontHeight);
+    Graphics2D graphics2D = img.createGraphics();
     HelperFunctions.setRenderingHints(graphics2D);
     graphics2D.setPaint(Color.WHITE);
-    graphics2D.fillRect(0, 0, 350, 100);
+    graphics2D.fillRect(0, 0, width, height);
     graphics2D.setPaint(Color.BLACK);
-    textLayout.draw(graphics2D, 15, 50);
+    graphics2D.setFont(font);
+    final var stringWidth = graphics2D.getFontMetrics().stringWidth(text);
+    final var padding = (stringWidth > width) ? 0 : (width - stringWidth) / 2;
+    final var scaleX = (stringWidth > width) ? width / ((double) stringWidth) : 1d;
+    graphics2D.scale(scaleX, 1d);
+    graphics2D.drawString(text, padding, fontHeight * 1.1f);
     graphics2D.dispose();
-    float[] kernel = {
+    final int kernelSize = (int) Math.ceil((Math.min(width, height) / 50.0));
-      1f / 9f, 1f / 9f, 1f / 9f,
+    ConvolveOp op =
-      1f / 9f, 1f / 9f, 1f / 9f,
+        new ConvolveOp(
-      1f / 9f, 1f / 9f, 1f / 9f
+            new Kernel(kernelSize, kernelSize, makeKernel(kernelSize)),
-    };
+            ConvolveOp.EDGE_NO_OP,
-    ConvolveOp op = new ConvolveOp(new Kernel(3, 3, kernel), ConvolveOp.EDGE_NO_OP, null);
+            null);
     BufferedImage img2 = op.filter(img, null);
     Graphics2D g2d = img2.createGraphics();
     HelperFunctions.setRenderingHints(g2d);
     g2d.setPaint(Color.WHITE);
-    textLayout.draw(g2d, 13, 50);
+    g2d.scale(scaleX, 1d);
+    g2d.setFont(font);
+    g2d.drawString(text, padding - kernelSize, fontHeight * 1.1f);
     g2d.dispose();
     ByteArrayOutputStream baos = new ByteArrayOutputStream();
     try {
@@ -74,8 +82,11 @@ public class ShadowTextCaptcha implements ChallengeProvider {
     return baos.toByteArray();
   }
 
-  public Challenge returnChallenge() {
+  public Challenge returnChallenge(String level, String size) {
     String secret = HelperFunctions.randomString(6);
-    return new Challenge(shadowText(secret), "image/png", secret.toLowerCase());
+    final int[] size2D = HelperFunctions.parseSize2D(size);
+    final int width = size2D[0];
+    final int height = size2D[1];
+    return new Challenge(shadowText(width, height, secret), "image/png", secret.toLowerCase());
   }
 }

src/main/java/lc/captchas/interfaces/ChallengeProvider.java

@@ -1,12 +1,12 @@
 package lc.captchas.interfaces;
 
-import java.util.Map;
 import java.util.List;
+import java.util.Map;
 
 public interface ChallengeProvider {
   public String getId();
 
-  public Challenge returnChallenge();
+  public Challenge returnChallenge(String level, String size);
 
   public boolean checkAnswer(String secret, String answer);
 

src/main/java/lc/misc/GifSequenceWriter.java

@@ -3,12 +3,12 @@
 
 package lc.misc;
 
-import javax.imageio.*;
-import javax.imageio.metadata.*;
-import javax.imageio.stream.*;
 import java.awt.image.*;
 import java.io.*;
 import java.util.Iterator;
+import javax.imageio.*;
+import javax.imageio.metadata.*;
+import javax.imageio.stream.*;
 
 public class GifSequenceWriter {
   protected ImageWriter gifWriter;

src/main/java/lc/misc/HelperFunctions.java

@@ -11,7 +11,14 @@ public class HelperFunctions {
     random.setSeed(seed);
   }
 
+  public static int[] parseSize2D(final String size) {
+    final String[] fields = size.split("x");
+    final int[] result = {Integer.parseInt(fields[0]), Integer.parseInt(fields[1])};
+    return result;
+  }
+
   public static void setRenderingHints(Graphics2D g2d) {
+    g2d.setRenderingHint(RenderingHints.KEY_ANTIALIASING, RenderingHints.VALUE_ANTIALIAS_ON);
     g2d.setRenderingHint(
         RenderingHints.KEY_TEXT_ANTIALIASING, RenderingHints.VALUE_TEXT_ANTIALIAS_ON);
     g2d.setRenderingHint(
@@ -23,7 +30,8 @@ public class HelperFunctions {
   public static final String safeNumbers = "23456789";
   public static final String allNumbers = safeNumbers + "10";
   public static final String specialCharacters = "$#%@&?";
-  public static final String safeCharacters = safeAlphabets + safeNumbers + specialCharacters;
+  public static final String safeAlphaNum = safeAlphabets + safeNumbers;
+  public static final String safeCharacters = safeAlphaNum + specialCharacters;
 
   public static String randomString(final int n) {
     return randomString(n, safeCharacters);

src/main/java/lc/misc/PngImageWriter.java

@@ -1,9 +1,9 @@
 package lc.misc;
 
+import java.awt.image.BufferedImage;
 import java.io.ByteArrayOutputStream;
 import java.io.IOException;
 import java.util.Iterator;
-
 import javax.imageio.IIOImage;
 import javax.imageio.ImageIO;
 import javax.imageio.ImageTypeSpecifier;
@@ -13,7 +13,6 @@ import javax.imageio.metadata.IIOInvalidTreeException;
 import javax.imageio.metadata.IIOMetadata;
 import javax.imageio.metadata.IIOMetadataNode;
 import javax.imageio.stream.ImageOutputStream;
-import java.awt.image.BufferedImage;
 
 public class PngImageWriter {
 
@@ -26,7 +25,8 @@ public class PngImageWriter {
         iw.hasNext(); ) {
       ImageWriter writer = iw.next();
       ImageWriteParam writeParam = writer.getDefaultWriteParam();
-      ImageTypeSpecifier typeSpecifier = ImageTypeSpecifier.createFromBufferedImageType(BufferedImage.TYPE_INT_RGB);
+      ImageTypeSpecifier typeSpecifier =
+          ImageTypeSpecifier.createFromBufferedImageType(BufferedImage.TYPE_INT_RGB);
       IIOMetadata metadata = writer.getDefaultImageMetadata(typeSpecifier, writeParam);
       if (metadata.isReadOnly() || !metadata.isStandardMetadataFormatSupported()) {
         continue;

src/main/java/org/limium/picoserve/Server.java

@@ -3,21 +3,21 @@
 
 package org.limium.picoserve;
 
-import java.net.InetSocketAddress;
+import com.sun.net.httpserver.HttpExchange;
+import com.sun.net.httpserver.HttpHandler;
+import com.sun.net.httpserver.HttpServer;
 import java.io.IOException;
-import java.util.List;
+import java.net.InetSocketAddress;
-import java.util.Map;
-import java.util.LinkedList;
-import java.util.concurrent.Executor;
-import java.util.regex.Pattern;
-import java.util.Arrays;
-import java.util.Optional;
-import java.util.stream.Collectors;
 import java.net.URLDecoder;
 import java.nio.charset.StandardCharsets;
-import com.sun.net.httpserver.HttpServer;
+import java.util.Arrays;
-import com.sun.net.httpserver.HttpHandler;
+import java.util.LinkedList;
-import com.sun.net.httpserver.HttpExchange;
+import java.util.List;
+import java.util.Map;
+import java.util.Optional;
+import java.util.concurrent.Executor;
+import java.util.regex.Pattern;
+import java.util.stream.Collectors;
 
 public final class Server {
   private final HttpServer server;

src/main/resources/index.html

@@ -20,9 +20,10 @@
     const levelInput = document.getElementById("levelInput").value
     const mediaInput = document.getElementById("mediaInput").value
     const typeInput = document.getElementById("typeInput").value
-    fetch("/v1/captcha", {
+    const sizeInput = document.getElementById("sizeInput").value
+    fetch("/v2/captcha", {
        method: 'POST',
-       body: JSON.stringify({level: levelInput, media: mediaInput, "input_type" : typeInput})
+       body: JSON.stringify({level: levelInput, media: mediaInput, "input_type" : typeInput, "size": sizeInput})
     }).then(async function(resp) {
       const respJson = await resp.json()
       if (resp.ok) {
@@ -30,7 +31,7 @@
         const resultDiv = document.getElementById("result")
         const result = `
           <p>Id: ${id}</p>
-          <p><img src="/v1/media?id=${id}" /> </p>
+          <p><img src="/v2/media?id=${id}" /> </p>
           <input type="text" id="answerInput" />
           <button onClick="submitAnswer('${id}')">Submit</button>
           <div id="answerResult" />
@@ -43,7 +44,7 @@
   }
   async function submitAnswer(id) {
     const ans = document.getElementById("answerInput").value;
-    const resp = await fetch("/v1/answer", {
+    const resp = await fetch("/v2/answer", {
        method: 'POST',
        body: JSON.stringify({id: id, answer: ans})
     })
@@ -70,6 +71,10 @@
       <span>Input Type</span>
       <input type="text" id="typeInput" value="text" />
     </div>
+    <div class="inputGroup">
+      <span>Input Size</span>
+      <input type="text" id="sizeInput" value="350x100" />
+    </div>
     <div class="inputGroup">
       <button onClick="loadCaptcha()">Get New CAPTCHA</button>
     </div>

src/main/scala/lc/Main.scala

@@ -25,6 +25,14 @@ object LCFramework {
       playgroundEnabled = config.playgroundEnabled,
       corsHeader = config.corsHeader
     )
+
+    Runtime.getRuntime.addShutdownHook(new Thread {
+      override def run(): Unit = {
+        println("Shutting down gracefully...")
+        backgroundTask.shutdown()
+      }
+    })
+
     server.start()
   }
 }

src/main/scala/lc/background/taskThread.scala

@@ -18,38 +18,73 @@ class BackgroundTask(config: Config, captchaManager: CaptchaManager) {
         val challengeGCPstmt = Statements.tlStmts.get.challengeGCPstmt
         challengeGCPstmt.executeUpdate()
 
-        val imageNumResult = Statements.tlStmts.get.getCountChallengeTable.executeQuery()
+        val allCombinations = allParameterCombinations()
-        val imageNum = if (imageNumResult.next()) {
+        val requiredCountPerCombination = Math.max(1, (config.bufferCount * 1.01) / allCombinations.size).toInt
-          imageNumResult.getInt("total")
+
-        } else {
+        for (param <- allCombinations) {
-          0
+          if (!shutdownInProgress) {
+            val countExisting = captchaManager.getCount(param).getOrElse(0)
+            val countRequired = requiredCountPerCombination - countExisting
+            if (countRequired > 0) {
+              val countCreate = Math.min(1.0 + requiredCountPerCombination / 10.0, countRequired).toInt
+              println(s"Creating $countCreate of $countRequired captchas for $param")
+
+              for (i <- 0 until countCreate) {
+                if (!shutdownInProgress) {
+                  captchaManager.generateChallenge(param)
+                }
+              }
+            }
           }
-
-        val throttle = (config.throttle * 1.1).toInt - imageNum
-
-        for (i <- 0 until throttle) {
-          captchaManager.generateChallenge(getRandomParam())
         }
       } catch { case exception: Exception => println(exception) }
     }
   }
 
+  private def allParameterCombinations(): List[Parameters] = {
+    (config.captchaConfig).flatMap { captcha =>
+      (captcha.allowedLevels).flatMap { level =>
+        (captcha.allowedMedia).flatMap { media =>
+          (captcha.allowedInputType).flatMap { inputType =>
+            (captcha.allowedSizes).map { size =>
+              Parameters(level, media, inputType, size)
+            }
+          }
+        }
+      }
+    }
+  }
+
   private def getRandomParam(): Parameters = {
     val captcha = pickRandom(config.captchaConfig)
     val level = pickRandom(captcha.allowedLevels)
     val media = pickRandom(captcha.allowedMedia)
     val inputType = pickRandom(captcha.allowedInputType)
+    val size = pickRandom(captcha.allowedSizes)
 
-    Parameters(level, media, inputType, Some(Size(0, 0)))
+    Parameters(level, media, inputType, size)
   }
 
   private def pickRandom[T](list: List[T]): T = {
     list(HelperFunctions.randomNumber(list.size))
   }
 
+  private val ex = new ScheduledThreadPoolExecutor(1)
+
   def beginThread(delay: Int): Unit = {
-    val ex = new ScheduledThreadPoolExecutor(1)
     ex.scheduleWithFixedDelay(task, 1, delay, TimeUnit.SECONDS)
   }
 
+  @volatile var shutdownInProgress = false
+
+  def shutdown(): Unit = {
+    println("  Shutting down background task...")
+    shutdownInProgress = true
+    ex.shutdown()
+    println("    Finished Shutting background task")
+    println("  Shutting down DB...")
+    Statements.tlStmts.get.shutdown.execute()
+    println("    Finished shutting down db")
+  }
+
 }

src/main/scala/lc/captchas/DebugCaptcha.scala

@@ -45,14 +45,14 @@ class DebugCaptcha extends ChallengeProvider {
     matches
   }
 
-  private def simpleText(text: String): Array[Byte] = {
+  private def simpleText(width: Int, height: Int, text: String): Array[Byte] = {
-    val img = new BufferedImage(350, 100, BufferedImage.TYPE_INT_RGB)
+    val img = new BufferedImage(width, height, BufferedImage.TYPE_INT_RGB)
     val font = new Font("Arial", Font.ROMAN_BASELINE, 56)
     val graphics2D = img.createGraphics()
     val textLayout = new TextLayout(text, font, graphics2D.getFontRenderContext())
     HelperFunctions.setRenderingHints(graphics2D)
     graphics2D.setPaint(Color.WHITE)
-    graphics2D.fillRect(0, 0, 350, 100)
+    graphics2D.fillRect(0, 0, width, height)
     graphics2D.setPaint(Color.BLACK)
     textLayout.draw(graphics2D, 15, 50)
     graphics2D.dispose()
@@ -66,8 +66,11 @@ class DebugCaptcha extends ChallengeProvider {
     baos.toByteArray()
   }
 
-  def returnChallenge(): Challenge = {
+  def returnChallenge(level: String, size: String): Challenge = {
     val secret = HelperFunctions.randomString(6, HelperFunctions.safeAlphabets)
-    new Challenge(simpleText(secret), "image/png", secret.toLowerCase())
+    val size2D = HelperFunctions.parseSize2D(size)
+    val width = size2D(0)
+    val height = size2D(1)
+    new Challenge(simpleText(width, height, secret), "image/png", secret.toLowerCase())
   }
 }

src/main/scala/lc/captchas/FilterChallenge.scala

@@ -10,6 +10,7 @@ import lc.captchas.interfaces.Challenge
 import java.util.{List => JavaList, Map => JavaMap}
 import java.io.ByteArrayOutputStream
 import lc.misc.PngImageWriter
+import lc.misc.HelperFunctions
 
 class FilterChallenge extends ChallengeProvider {
   def getId = "FilterChallenge"
@@ -29,31 +30,38 @@ class FilterChallenge extends ChallengeProvider {
     )
   }
 
-  def returnChallenge(): Challenge = {
+  private val filterTypes = List(new FilterType1, new FilterType2)
-    val filterTypes = List(new FilterType1, new FilterType2)
+
+  def returnChallenge(level: String, size: String): Challenge = {
+    val mediumLevel = level == "medium"
     val r = new scala.util.Random
-    val alphabet = "abcdefghijklmnopqrstuvwxyz"
+    val characters = if (mediumLevel) HelperFunctions.safeAlphaNum else HelperFunctions.safeCharacters
-    val n = 8
+    val n = if (mediumLevel) 5 else 7
-    val secret = LazyList.continually(r.nextInt(alphabet.size)).map(alphabet).take(n).mkString
+    val secret = LazyList.continually(r.nextInt(characters.size)).map(characters).take(n).mkString
-    val canvas = new BufferedImage(225, 50, BufferedImage.TYPE_INT_RGB)
+    val size2D = HelperFunctions.parseSize2D(size)
+    val width = size2D(0)
+    val height = size2D(1)
+    val canvas = new BufferedImage(width, height, BufferedImage.TYPE_INT_RGB)
     val g = canvas.createGraphics()
+    val fontHeight = (height * 0.6).toInt
     g.setColor(Color.WHITE)
     g.fillRect(0, 0, canvas.getWidth, canvas.getHeight)
     g.setColor(Color.BLACK)
-    g.setFont(new Font("Serif", Font.PLAIN, 30))
+    val font = new Font("Serif", Font.BOLD, fontHeight)
-    g.drawString(secret, 5, 30)
+    g.setFont(font)
+    val stringWidth = g.getFontMetrics().stringWidth(secret)
+    val scaleX = if (stringWidth > width) width / (stringWidth.toDouble) else 1d
+    val margin = if (stringWidth > width) 0 else (width - stringWidth)
+    val xOffset = (margin * r.nextDouble).toInt
+    g.scale(scaleX, 1d)
+    g.drawString(secret, xOffset, fontHeight)
     g.dispose()
     var image = ImmutableImage.fromAwt(canvas)
-    val s = scala.util.Random.nextInt(2)
+    val s = r.nextInt(2)
-    image = filterTypes(s).applyFilter(image)
+    image = filterTypes(s).applyFilter(image, !mediumLevel)
     val img = image.awt()
     val baos = new ByteArrayOutputStream()
-    try {
     PngImageWriter.write(baos, img);
-    } catch {
-      case e: Exception =>
-        e.printStackTrace()
-    }
     new Challenge(baos.toByteArray, "image/png", secret)
   }
   def checkAnswer(secret: String, answer: String): Boolean = {
@@ -62,14 +70,15 @@ class FilterChallenge extends ChallengeProvider {
 }
 
 trait FilterType {
-  def applyFilter(image: ImmutableImage): ImmutableImage
+  def applyFilter(image: ImmutableImage, hardLevel: Boolean): ImmutableImage
 }
 
 class FilterType1 extends FilterType {
-  override def applyFilter(image: ImmutableImage): ImmutableImage = {
+  override def applyFilter(image: ImmutableImage, hardLevel: Boolean): ImmutableImage = {
-    val blur = new GaussianBlurFilter(2)
+    val radius = if (hardLevel) 3 else 2
+    val blur = new GaussianBlurFilter(radius)
     val smear = new SmearFilter(com.sksamuel.scrimage.filter.SmearType.Circles, 10, 10, 10, 0, 1)
-    val diffuse = new DiffuseFilter(2)
+    val diffuse = new DiffuseFilter(radius.toFloat)
     blur.apply(image)
     diffuse.apply(image)
     smear.apply(image)
@@ -78,9 +87,10 @@ class FilterType1 extends FilterType {
 }
 
 class FilterType2 extends FilterType {
-  override def applyFilter(image: ImmutableImage): ImmutableImage = {
+  override def applyFilter(image: ImmutableImage, hardLevel: Boolean): ImmutableImage = {
+    val radius = if (hardLevel) 2f else 1f
     val smear = new SmearFilter(com.sksamuel.scrimage.filter.SmearType.Circles, 10, 10, 10, 0, 1)
-    val diffuse = new DiffuseFilter(1)
+    val diffuse = new DiffuseFilter(radius)
     val ripple = new RippleFilter(com.sksamuel.scrimage.filter.RippleType.Noise, 1, 1, 0.005.toFloat, 0.005.toFloat)
     diffuse.apply(image)
     ripple.apply(image)

src/main/scala/lc/captchas/LabelCaptcha.scala

@@ -40,7 +40,7 @@ class LabelCaptcha extends ChallengeProvider {
     )
   }
 
-  def returnChallenge(): Challenge =
+  def returnChallenge(level: String, size: String): Challenge =
     synchronized {
       val r = scala.util.Random.nextInt(knownFiles.length)
       val s = scala.util.Random.nextInt(unknownFiles.length)

src/main/scala/lc/captchas/RainDropsCaptcha.scala

@@ -11,6 +11,7 @@ import lc.captchas.interfaces.ChallengeProvider
 import lc.captchas.interfaces.Challenge
 import lc.misc.GifSequenceWriter
 import java.util.{List => JavaList, Map => JavaMap}
+import lc.misc.HelperFunctions
 
 class Drop {
   var x = 0
@@ -24,8 +25,6 @@ class Drop {
 }
 
 class RainDropsCP extends ChallengeProvider {
-  private val alphabet = "abcdefghijklmnopqrstuvwxyz"
-  private val n = 6
   private val bgColor = new Color(200, 200, 200)
   private val textColor = new Color(208, 208, 218)
   private val textHighlightColor = new Color(100, 100, 125)
@@ -56,11 +55,13 @@ class RainDropsCP extends ChallengeProvider {
     })
   }
 
-  def returnChallenge(): Challenge = {
+  def returnChallenge(level: String, size: String): Challenge = {
     val r = new scala.util.Random
-    val secret = LazyList.continually(r.nextInt(alphabet.size)).map(alphabet).take(n).mkString
+    val n = if (level == "easy") 4 else 6
-    val width = 450
+    val secret = HelperFunctions.randomString(n, HelperFunctions.safeAlphaNum)
-    val height = 100
+    val size2D = HelperFunctions.parseSize2D(size)
+    val width = size2D(0)
+    val height = size2D(1)
     val imgType = BufferedImage.TYPE_INT_RGB
     val xOffset = 2 + r.nextInt(3)
     val xBias = (height / 10) - 2
@@ -80,7 +81,8 @@ class RainDropsCP extends ChallengeProvider {
       xOffset
     )
 
-    val baseFont = new Font(Font.MONOSPACED, Font.BOLD, 80)
+    val fontHeight = (height * 0.5f).toInt
+    val baseFont = new Font(Font.MONOSPACED, Font.BOLD, fontHeight)
     val attributes = new java.util.HashMap[TextAttribute, Object]()
     attributes.put(TextAttribute.TRACKING, Double.box(0.2))
     attributes.put(TextAttribute.WEIGHT, TextAttribute.WEIGHT_EXTRABOLD)
@@ -117,17 +119,22 @@ class RainDropsCP extends ChallengeProvider {
         }
       }
 
-      // center the text
       g.setFont(spacedFont)
-      val textWidth = g.getFontMetrics().charsWidth(secret.toCharArray, 0, secret.toCharArray.length)
+      val textWidth = g.getFontMetrics().stringWidth(secret)
-      val textX = (width - textWidth) / 2
+      val scaleX = if (textWidth > width) width / textWidth.toDouble else 1.0d
+      g.scale(scaleX, 1)
 
-      // paint the top outline
+      // center the text
+      val textX = if (textWidth > width) 0 else ((width - textWidth) / 2)
+
+      // this will be overlapped by the following text to show the top outline because of the offset
+      val yOffset = (fontHeight * 0.01).ceil.toInt
       g.setColor(textHighlightColor)
-      g.drawString(secret, textX, 69)
+      g.drawString(secret, textX, (fontHeight * 1.1).toInt - yOffset)
+
       // paint the text
       g.setColor(textColor)
-      g.drawString(secret, textX, 70)
+      g.drawString(secret, textX, (fontHeight * 1.1).toInt)
 
       g.dispose()
       writer.writeToSequence(canvas)

src/main/scala/lc/core/captchaFields.scala

@@ -10,7 +10,7 @@ object ParametersEnum extends Enumeration {
   val ALLOWEDLEVELS: Value = Value("allowedLevels")
   val ALLOWEDMEDIA: Value = Value("allowedMedia")
   val ALLOWEDINPUTTYPE: Value = Value("allowedInputType")
-
+  val ALLOWEDSIZES: Value = Value("allowedSizes")
 }
 
 object AttributesEnum extends Enumeration {
@@ -21,12 +21,12 @@ object AttributesEnum extends Enumeration {
   val PORT: Value = Value("port")
   val ADDRESS: Value = Value("address")
   val CAPTCHA_EXPIRY_TIME_LIMIT: Value = Value("captchaExpiryTimeLimit")
-  val THROTTLE: Value = Value("throttle")
+  val BUFFER_COUNT: Value = Value("bufferCount")
   val THREAD_DELAY: Value = Value("threadDelay")
   val PLAYGROUND_ENABLED: Value = Value("playgroundEnabled")
   val CORS_HEADER: Value = Value("corsHeader")
   val CONFIG: Value = Value("config")
-  val MAX_ATTEMPTS: Value = Value("maxAttempts")
+  val MAX_ATTEMPTS_RATIO: Value = Value("maxAttemptsRatio")
 }
 
 object ResultEnum extends Enumeration {

src/main/scala/lc/core/captchaManager.scala

@@ -34,17 +34,19 @@ class CaptchaManager(config: Config, captchaProviders: CaptchaProviders) {
   }
 
   def generateChallenge(param: Parameters): Option[Int] = {
-    val provider = captchaProviders.getProvider(param)
+    try {
-    provider match {
+      captchaProviders.getProvider(param).flatMap { provider =>
-      case Some(value) => {
+        val providerId = provider.getId()
-        val providerId = value.getId()
+        val challenge = provider.returnChallenge(param.level, param.size)
-        val challenge = value.returnChallenge()
         val blob = new ByteArrayInputStream(challenge.content)
-        val token = insertCaptcha(value, challenge, providerId, param, blob)
+        val token = insertCaptcha(provider, challenge, providerId, param, blob)
         // println("Added new challenge: " + token.toString)
         token.map(_.toInt)
       }
-      case None => None
+    } catch {
+      case e: Exception =>
+        e.printStackTrace()
+        None
     }
   }
 
@@ -62,7 +64,8 @@ class CaptchaManager(config: Config, captchaProviders: CaptchaProviders) {
     insertPstmt.setString(4, challenge.contentType)
     insertPstmt.setString(5, param.level)
     insertPstmt.setString(6, param.input_type)
-    insertPstmt.setBlob(7, blob)
+    insertPstmt.setString(7, param.size)
+    insertPstmt.setBlob(8, blob)
     insertPstmt.executeUpdate()
     val rs: ResultSet = insertPstmt.getGeneratedKeys()
     if (rs.next()) {
@@ -105,11 +108,31 @@ class CaptchaManager(config: Config, captchaProviders: CaptchaProviders) {
     }
   }
 
+  def getCount(param: Parameters): Option[Int] = {
+    val countPstmt = Statements.tlStmts.get.countForParameterPstmt
+    countPstmt.setString(1, param.level)
+    countPstmt.setString(2, param.media)
+    countPstmt.setString(3, param.input_type)
+    countPstmt.setString(4, param.size.toString())
+    val rs = countPstmt.executeQuery()
+    if (rs.next()) {
+      Some(rs.getInt("count"))
+    } else {
+      None
+    }
+  }
+
   private def getToken(param: Parameters): Option[Int] = {
+    val count = getCount(param).getOrElse(0)
+    if (count == 0) {
+      None
+    } else {
       val tokenPstmt = Statements.tlStmts.get.tokenPstmt
       tokenPstmt.setString(1, param.level)
       tokenPstmt.setString(2, param.media)
       tokenPstmt.setString(3, param.input_type)
+      tokenPstmt.setString(4, param.size)
+      tokenPstmt.setInt(5, count)
       val rs = tokenPstmt.executeQuery()
       if (rs.next()) {
         Some(rs.getInt("token"))
@@ -117,6 +140,7 @@ class CaptchaManager(config: Config, captchaProviders: CaptchaProviders) {
         None
       }
     }
+  }
 
   private def updateAttempted(token: Int): Unit = {
     val updateAttemptedPstmt = Statements.tlStmts.get.updateAttemptedPstmt

src/main/scala/lc/core/captchaProviders.scala

@@ -19,7 +19,7 @@ class CaptchaProviders(config: Config) {
 
   def generateChallengeSamples(): Map[String, Challenge] = {
     providers.map { case (key, provider) =>
-      (key, provider.returnChallenge())
+      (key, provider.returnChallenge("easy", "350x100"))
     }
   }
 
@@ -35,6 +35,7 @@ class CaptchaProviders(config: Config) {
       if configValue.allowedLevels.contains(param.level)
       if configValue.allowedMedia.contains(param.media)
       if configValue.allowedInputType.contains(param.input_type)
+      if configValue.allowedSizes.contains(param.size)
     } yield (configValue.name, configValue.config)
 
     val providerFilter = for {

src/main/scala/lc/core/config.scala

@@ -45,13 +45,13 @@ class Config(configFilePath: String) {
 
   val port: Int = configFields.portInt.getOrElse(8888)
   val address: String = configFields.address.getOrElse("0.0.0.0")
-  val throttle: Int = configFields.throttleInt.getOrElse(1000)
+  val bufferCount: Int = configFields.bufferCountInt.getOrElse(1000)
   val seed: Int = configFields.seedInt.getOrElse(375264328)
   val captchaExpiryTimeLimit: Int = configFields.captchaExpiryTimeLimitInt.getOrElse(5)
   val threadDelay: Int = configFields.threadDelayInt.getOrElse(2)
   val playgroundEnabled: Boolean = configFields.playgroundEnabledBool.getOrElse(true)
   val corsHeader: String = configFields.corsHeader.getOrElse("")
-  val maxAttempts: Int = configFields.maxAttemptsInt.getOrElse(10)
+  val maxAttempts: Int = Math.max(1, (configFields.maxAttemptsRatioFloat.getOrElse(0.01f) * bufferCount).toInt)
 
   private val captchaConfigJson = (configJson \ "captchas")
   val captchaConfigTransform: JValue = captchaConfigJson transformField { case JField("config", JObject(config)) =>
@@ -70,17 +70,18 @@ class Config(configFilePath: String) {
         (AttributesEnum.PORT.toString -> 8888) ~
         (AttributesEnum.ADDRESS.toString -> "0.0.0.0") ~
         (AttributesEnum.CAPTCHA_EXPIRY_TIME_LIMIT.toString -> 5) ~
-        (AttributesEnum.THROTTLE.toString -> 1000) ~
+        (AttributesEnum.BUFFER_COUNT.toString -> 1000) ~
         (AttributesEnum.THREAD_DELAY.toString -> 2) ~
         (AttributesEnum.PLAYGROUND_ENABLED.toString -> true) ~
         (AttributesEnum.CORS_HEADER.toString -> "") ~
-        (AttributesEnum.MAX_ATTEMPTS.toString -> 10) ~
+        (AttributesEnum.MAX_ATTEMPTS_RATIO.toString -> 0.01f) ~
         ("captchas" -> List(
           (
             (AttributesEnum.NAME.toString -> "FilterChallenge") ~
               (ParametersEnum.ALLOWEDLEVELS.toString -> List("medium", "hard")) ~
               (ParametersEnum.ALLOWEDMEDIA.toString -> List("image/png")) ~
               (ParametersEnum.ALLOWEDINPUTTYPE.toString -> List("text")) ~
+              (ParametersEnum.ALLOWEDSIZES.toString -> List("350x100")) ~
               (AttributesEnum.CONFIG.toString -> JObject())
           ),
           (
@@ -88,6 +89,7 @@ class Config(configFilePath: String) {
               (ParametersEnum.ALLOWEDLEVELS.toString -> List("hard")) ~
               (ParametersEnum.ALLOWEDMEDIA.toString -> List("image/gif")) ~
               (ParametersEnum.ALLOWEDINPUTTYPE.toString -> List("text")) ~
+              (ParametersEnum.ALLOWEDSIZES.toString -> List("350x100")) ~
               (AttributesEnum.CONFIG.toString -> JObject())
           ),
           (
@@ -95,6 +97,7 @@ class Config(configFilePath: String) {
               (ParametersEnum.ALLOWEDLEVELS.toString -> List("easy")) ~
               (ParametersEnum.ALLOWEDMEDIA.toString -> List("image/png")) ~
               (ParametersEnum.ALLOWEDINPUTTYPE.toString -> List("text")) ~
+              (ParametersEnum.ALLOWEDSIZES.toString -> List("350x100")) ~
               (AttributesEnum.CONFIG.toString -> JObject())
           ),
           (
@@ -102,6 +105,7 @@ class Config(configFilePath: String) {
               (ParametersEnum.ALLOWEDLEVELS.toString -> List("easy", "medium")) ~
               (ParametersEnum.ALLOWEDMEDIA.toString -> List("image/gif")) ~
               (ParametersEnum.ALLOWEDINPUTTYPE.toString -> List("text")) ~
+              (ParametersEnum.ALLOWEDSIZES.toString -> List("350x100")) ~
               (AttributesEnum.CONFIG.toString -> JObject())
           )
         ))

src/main/scala/lc/core/models.scala

@@ -5,7 +5,7 @@ import lc.core.Config.formats
 
 trait ByteConvert { def toBytes(): Array[Byte] }
 case class Size(height: Int, width: Int)
-case class Parameters(level: String, media: String, input_type: String, size: Option[Size])
+case class Parameters(level: String, media: String, input_type: String, size: String)
 case class Id(id: String) extends ByteConvert { def toBytes(): Array[Byte] = { write(this).getBytes } }
 case class Image(image: Array[Byte]) extends ByteConvert { def toBytes(): Array[Byte] = { image } }
 case class Answer(answer: String, id: String)
@@ -16,28 +16,32 @@ case class CaptchaConfig(
     allowedLevels: List[String],
     allowedMedia: List[String],
     allowedInputType: List[String],
+    allowedSizes: List[String],
     config: String
 )
 case class ConfigField(
     port: Option[Integer],
     address: Option[String],
-    throttle: Option[Integer],
+    bufferCount: Option[Integer],
     seed: Option[Integer],
     captchaExpiryTimeLimit: Option[Integer],
     threadDelay: Option[Integer],
     playgroundEnabled: Option[java.lang.Boolean],
     corsHeader: Option[String],
-    maxAttempts: Option[Integer]
+    maxAttemptsRatio: Option[java.lang.Float]
 ) {
   lazy val portInt: Option[Int] = mapInt(port)
-  lazy val throttleInt: Option[Int] = mapInt(throttle)
+  lazy val bufferCountInt: Option[Int] = mapInt(bufferCount)
   lazy val seedInt: Option[Int] = mapInt(seed)
   lazy val captchaExpiryTimeLimitInt: Option[Int] = mapInt(captchaExpiryTimeLimit)
   lazy val threadDelayInt: Option[Int] = mapInt(threadDelay)
-  lazy val maxAttemptsInt: Option[Int] = mapInt(maxAttempts)
+  lazy val maxAttemptsRatioFloat: Option[Float] = mapFloat(maxAttemptsRatio)
-  lazy val playgroundEnabledBool: Option[Boolean] = playgroundEnabled.map(_ || true)
+  lazy val playgroundEnabledBool: Option[Boolean] = playgroundEnabled.map(_ || false)
 
   private def mapInt(x: Option[Integer]): Option[Int] = {
     x.map(_ + 0)
   }
+  private def mapFloat(x: Option[java.lang.Float]): Option[Float] = {
+    x.map(_ + 0.0f)
+  }
 }

src/main/scala/lc/database/DB.scala

@@ -3,7 +3,8 @@ package lc.database
 import java.sql.{Connection, DriverManager, Statement}
 
 class DBConn() {
-  val con: Connection = DriverManager.getConnection("jdbc:h2:./data/H2/captcha2", "sa", "")
+  val con: Connection =
+    DriverManager.getConnection("jdbc:h2:./data/H2/captcha3;MAX_COMPACT_TIME=8000;DB_CLOSE_ON_EXIT=FALSE", "sa", "")
 
   def getStatement(): Statement = {
     con.createStatement()

src/main/scala/lc/database/statements.scala

@@ -17,6 +17,7 @@ class Statements(dbConn: DBConn, maxAttempts: Int) {
       "contentType varchar, " +
       "contentLevel varchar, " +
       "contentInput varchar, " +
+      "size varchar, " +
       "image blob, " +
       "attempted int default 0, " +
       "PRIMARY KEY(token));" +
@@ -37,8 +38,8 @@ class Statements(dbConn: DBConn, maxAttempts: Int) {
 
   val insertPstmt: PreparedStatement = dbConn.con.prepareStatement(
     "INSERT INTO " +
-      "challenge(id, secret, provider, contentType, contentLevel, contentInput, image) " +
+      "challenge(id, secret, provider, contentType, contentLevel, contentInput, size, image) " +
-      "VALUES (?, ?, ?, ?, ?, ?, ?)",
+      "VALUES (?, ?, ?, ?, ?, ?, ?, ?)",
     Statement.RETURN_GENERATED_KEYS
   )
 
@@ -70,6 +71,18 @@ class Statements(dbConn: DBConn, maxAttempts: Int) {
       "WHERE token = ?;"
   )
 
+  val countForParameterPstmt: PreparedStatement = dbConn.con.prepareStatement(
+    s"""
+      SELECT count(*) as count
+        FROM challenge
+        WHERE attempted < $maxAttempts AND
+        contentLevel = ? AND
+        contentType = ? AND
+        contentInput = ? AND
+        size = ?
+        """
+  )
+
   val tokenPstmt: PreparedStatement = dbConn.con.prepareStatement(
     s"""
       SELECT token, attempted
@@ -77,8 +90,11 @@ class Statements(dbConn: DBConn, maxAttempts: Int) {
         WHERE attempted < $maxAttempts AND
         contentLevel = ? AND
         contentType = ? AND
-        contentInput = ?
+        contentInput = ? AND
-        ORDER BY attempted ASC LIMIT 1"""
+        size = ?
+        LIMIT 1
+        OFFSET FLOOR(RAND()*?)
+         """
   )
 
   val deleteAnswerPstmt: PreparedStatement = dbConn.con.prepareStatement(
@@ -107,6 +123,14 @@ class Statements(dbConn: DBConn, maxAttempts: Int) {
     "SELECT * FROM mapId"
   )
 
+  val shutdown: PreparedStatement = dbConn.con.prepareStatement(
+    "SHUTDOWN"
+  )
+
+  val shutdownCompact: PreparedStatement = dbConn.con.prepareStatement(
+    "SHUTDOWN COMPACT"
+  )
+
 }
 
 object Statements {

src/main/scala/lc/server/Server.scala

@@ -13,7 +13,13 @@ import java.net.InetSocketAddress
 import java.util
 import scala.jdk.CollectionConverters._
 
-class Server(address: String, port: Int, captchaManager: CaptchaManager, playgroundEnabled: Boolean, corsHeader: String) {
+class Server(
+    address: String,
+    port: Int,
+    captchaManager: CaptchaManager,
+    playgroundEnabled: Boolean,
+    corsHeader: String
+) {
   var headerMap: util.Map[String, util.List[String]] = _
   if (corsHeader.nonEmpty) {
     headerMap = Map("Access-Control-Allow-Origin" -> List(corsHeader).asJava).asJava
@@ -23,7 +29,7 @@ class Server(address: String, port: Int, captchaManager: CaptchaManager, playgro
     .address(new InetSocketAddress(address, port))
     .backlog(32)
     .POST(
-      "/v1/captcha",
+      "/v2/captcha",
       (request) => {
         val json = parse(request.getBodyString())
         val param = json.extract[Parameters]
@@ -32,7 +38,7 @@ class Server(address: String, port: Int, captchaManager: CaptchaManager, playgro
       }
     )
     .GET(
-      "/v1/media",
+      "/v2/media",
       (request) => {
         val params = request.getQueryParams()
         val result = if (params.containsKey("id")) {
@@ -46,7 +52,7 @@ class Server(address: String, port: Int, captchaManager: CaptchaManager, playgro
       }
     )
     .POST(
-      "/v1/answer",
+      "/v2/answer",
       (request) => {
         val json = parse(request.getBodyString())
         val answer = json.extract[Answer]
@@ -63,6 +69,20 @@ class Server(address: String, port: Int, captchaManager: CaptchaManager, playgro
         new StringResponse(200, str)
       }
     )
+    serverBuilder.GET(
+      "/",
+      (_) => {
+        val str = """
+        <html>
+          <h2>Welcome to LibreCaptcha server</h2>
+          <h3><a href="/demo/index.html">Link to Demo</a></h3>
+          <h3>API is served at <b>/v2/</b></h3>
+        </html>
+        """
+        new StringResponse(200, str)
+      }
+    )
+    println("Playground enabled on /demo/index.html")
   }
 
   val server: picoserve.Server = serverBuilder.build()

tests/debug-config.json

@@ -3,16 +3,17 @@
   "port" : 8888,
   "address" : "0.0.0.0",
   "captchaExpiryTimeLimit" : 5,
-  "throttle" : 10,
+  "bufferCount" : 10,
   "threadDelay" : 2,
   "playgroundEnabled" : false,
   "corsHeader" : "*",
-  "maxAttempts" : 20,
+  "maxAttemptsRatio" : 0.01,
   "captchas" : [ {
     "name" : "DebugCaptcha",
     "allowedLevels" : [ "debug" ],
     "allowedMedia" : [ "image/png" ],
     "allowedInputType" : [ "text" ],
+    "allowedSizes" : [ "350x100" ],
     "config" : { }
   }]
 }

tests/locustfile-functional.py

@@ -22,9 +22,9 @@ class QuickStartUser(SequentialTaskSet):
 
     @task
     def captcha(self):
-        captcha_params = {"level":"debug","media":"image/png","input_type":"text"}
+        captcha_params = {"level":"debug","media":"image/png","input_type":"text", "size":"350x100"}
 
-        with self.client.post(path="/v1/captcha", json=captcha_params, name="/captcha", catch_response = True) as resp:
+        with self.client.post(path="/v2/captcha", json=captcha_params, name="/captcha", catch_response = True) as resp:
           if resp.status_code != 200:
             resp.failure("Status was not 200: " + resp.text)
           captchaJson = resp.json()
@@ -32,7 +32,7 @@ class QuickStartUser(SequentialTaskSet):
           if not uuid:
             resp.failure("uuid not returned on /captcha endpoint: " + resp.text)
 
-        with self.client.get(path="/v1/media?id=%s" % uuid, name="/media", stream=True, catch_response = True) as resp:
+        with self.client.get(path="/v2/media?id=%s" % uuid, name="/media", stream=True, catch_response = True) as resp:
           if resp.status_code != 200:
             resp.failure("Status was not 200: " + resp.text)
 
@@ -41,7 +41,7 @@ class QuickStartUser(SequentialTaskSet):
         ocrAnswer = self.solve(uuid, media)
 
         answerBody = {"answer": ocrAnswer,"id": uuid}
-        with self.client.post(path='/v1/answer', json=answerBody, name="/answer", catch_response=True) as resp:
+        with self.client.post(path='/v2/answer', json=answerBody, name="/answer", catch_response=True) as resp:
           if resp.status_code != 200:
               resp.failure("Status was not 200: " + resp.text)
           else:

tests/locustfile.py

@@ -24,9 +24,9 @@ class QuickStartUser(SequentialTaskSet):
     @task
     def captcha(self):
         # TODO: Iterate over parameters for a more comprehensive test
-        captcha_params = {"level":"easy","media":"image/png","input_type":"text"}
+        captcha_params = {"level":"easy","media":"image/png","input_type":"text", "size":"350x100"}
 
-        resp = self.client.post(path="/v1/captcha", json=captcha_params, name="/captcha")
+        resp = self.client.post(path="/v2/captcha", json=captcha_params, name="/captcha")
         if resp.status_code != 200:
             print("\nError on /captcha endpoint: ")
             print(resp)
@@ -36,14 +36,14 @@ class QuickStartUser(SequentialTaskSet):
         uuid = json.loads(resp.text).get("id")
         answerBody = {"answer": "qwer123","id": uuid}
 
-        resp = self.client.get(path="/v1/media?id=%s" % uuid, name="/media")
+        resp = self.client.get(path="/v2/media?id=%s" % uuid, name="/media")
         if resp.status_code != 200:
             print("\nError on /media endpoint: ")
             print(resp)
             print(resp.text)
             print("----------------END.MEDIA-------------------\n\n")
 
-        resp = self.client.post(path='/v1/answer', json=answerBody, name="/answer")
+        resp = self.client.post(path='/v2/answer', json=answerBody, name="/answer")
         if resp.status_code != 200:
             print("\nError on /answer endpoint: ")
             print(resp)

tests/run.sh

@@ -4,7 +4,7 @@ python3 -m venv testEnv
 source ./testEnv/bin/activate
 pip install locust
 mkdir -p data/
-java -jar target/scala-3.1.1/LibreCaptcha.jar &
+java -jar target/scala-3.6.2/LibreCaptcha.jar &
 JAVA_PID=$!
 sleep 4
 
@@ -22,7 +22,7 @@ echo Run functional test
 cp data/config.json data/config.json.bak
 cp tests/debug-config.json data/config.json
 
-java -jar target/scala-3.1.1/LibreCaptcha.jar &
+java -jar target/scala-3.6.2/LibreCaptcha.jar &
 JAVA_PID=$!
 sleep 4