.gitignore

+HELP.md
+.gradle
+build/
+!gradle/wrapper/gradle-wrapper.jar
+!**/src/main/**
+!**/src/test/**
+
+### STS ###
+.apt_generated
+.classpath
+.factorypath
+.project
+.settings
+.springBeans
+.sts4-cache
+
+### IntelliJ IDEA ###
+.idea
+*.iws
+*.iml
+*.ipr
+out/
+
+### NetBeans ###
+/nbproject/private/
+/nbbuild/
+/dist/
+/nbdist/
+/.nb-gradle/
+
+### VS Code ###
+.vscode/

build.gradle

+plugins {
+	id 'org.springframework.boot' version '2.3.1.RELEASE'
+	id 'io.spring.dependency-management' version '1.0.9.RELEASE'
+	id 'java'
+}
+
+group = 'au.com.tpic'
+version = '0.0.1-SNAPSHOT'
+sourceCompatibility = '14'
+
+configurations {
+	compileOnly {
+		extendsFrom annotationProcessor
+	}
+}
+
+repositories {
+	mavenCentral()
+}
+
+dependencies {
+	compileOnly 'org.projectlombok:lombok'
+	annotationProcessor 'org.projectlombok:lombok'
+	annotationProcessor "org.springframework.boot:spring-boot-configuration-processor"
+	implementation 'org.springframework.boot:spring-boot-starter-web'
+	implementation group: 'com.google.guava', name: 'guava', version: '29.0-jre'
+	testImplementation('org.springframework.boot:spring-boot-starter-test') {
+		exclude group: 'org.junit.vintage', module: 'junit-vintage-engine'
+	}
+}
+
+test {
+	useJUnitPlatform()
+}

gradle/wrapper/gradle-wrapper.properties

+#Tue Jun 16 12:21:27 AEST 2020
+distributionUrl=https\://services.gradle.org/distributions/gradle-6.4.1-all.zip
+distributionBase=GRADLE_USER_HOME
+distributionPath=wrapper/dists
+zipStorePath=wrapper/dists
+zipStoreBase=GRADLE_USER_HOME

gradlew

+#!/usr/bin/env sh
+
+#
+# Copyright 2015 the original author or authors.
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#      https://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+#
+
+##############################################################################
+##
+##  Gradle start up script for UN*X
+##
+##############################################################################
+
+# Attempt to set APP_HOME
+# Resolve links: $0 may be a link
+PRG="$0"
+# Need this for relative symlinks.
+while [ -h "$PRG" ] ; do
+    ls=`ls -ld "$PRG"`
+    link=`expr "$ls" : '.*-> \(.*\)$'`
+    if expr "$link" : '/.*' > /dev/null; then
+        PRG="$link"
+    else
+        PRG=`dirname "$PRG"`"/$link"
+    fi
+done
+SAVED="`pwd`"
+cd "`dirname \"$PRG\"`/" >/dev/null
+APP_HOME="`pwd -P`"
+cd "$SAVED" >/dev/null
+
+APP_NAME="Gradle"
+APP_BASE_NAME=`basename "$0"`
+
+# Add default JVM options here. You can also use JAVA_OPTS and GRADLE_OPTS to pass JVM options to this script.
+DEFAULT_JVM_OPTS='"-Xmx64m" "-Xms64m"'
+
+# Use the maximum available, or set MAX_FD != -1 to use that value.
+MAX_FD="maximum"
+
+warn () {
+    echo "$*"
+}
+
+die () {
+    echo
+    echo "$*"
+    echo
+    exit 1
+}
+
+# OS specific support (must be 'true' or 'false').
+cygwin=false
+msys=false
+darwin=false
+nonstop=false
+case "`uname`" in
+  CYGWIN* )
+    cygwin=true
+    ;;
+  Darwin* )
+    darwin=true
+    ;;
+  MINGW* )
+    msys=true
+    ;;
+  NONSTOP* )
+    nonstop=true
+    ;;
+esac
+
+CLASSPATH=$APP_HOME/gradle/wrapper/gradle-wrapper.jar
+
+
+# Determine the Java command to use to start the JVM.
+if [ -n "$JAVA_HOME" ] ; then
+    if [ -x "$JAVA_HOME/jre/sh/java" ] ; then
+        # IBM's JDK on AIX uses strange locations for the executables
+        JAVACMD="$JAVA_HOME/jre/sh/java"
+    else
+        JAVACMD="$JAVA_HOME/bin/java"
+    fi
+    if [ ! -x "$JAVACMD" ] ; then
+        die "ERROR: JAVA_HOME is set to an invalid directory: $JAVA_HOME
+
+Please set the JAVA_HOME variable in your environment to match the
+location of your Java installation."
+    fi
+else
+    JAVACMD="java"
+    which java >/dev/null 2>&1 || die "ERROR: JAVA_HOME is not set and no 'java' command could be found in your PATH.
+
+Please set the JAVA_HOME variable in your environment to match the
+location of your Java installation."
+fi
+
+# Increase the maximum file descriptors if we can.
+if [ "$cygwin" = "false" -a "$darwin" = "false" -a "$nonstop" = "false" ] ; then
+    MAX_FD_LIMIT=`ulimit -H -n`
+    if [ $? -eq 0 ] ; then
+        if [ "$MAX_FD" = "maximum" -o "$MAX_FD" = "max" ] ; then
+            MAX_FD="$MAX_FD_LIMIT"
+        fi
+        ulimit -n $MAX_FD
+        if [ $? -ne 0 ] ; then
+            warn "Could not set maximum file descriptor limit: $MAX_FD"
+        fi
+    else
+        warn "Could not query maximum file descriptor limit: $MAX_FD_LIMIT"
+    fi
+fi
+
+# For Darwin, add options to specify how the application appears in the dock
+if $darwin; then
+    GRADLE_OPTS="$GRADLE_OPTS \"-Xdock:name=$APP_NAME\" \"-Xdock:icon=$APP_HOME/media/gradle.icns\""
+fi
+
+# For Cygwin or MSYS, switch paths to Windows format before running java
+if [ "$cygwin" = "true" -o "$msys" = "true" ] ; then
+    APP_HOME=`cygpath --path --mixed "$APP_HOME"`
+    CLASSPATH=`cygpath --path --mixed "$CLASSPATH"`
+    
+    JAVACMD=`cygpath --unix "$JAVACMD"`
+
+    # We build the pattern for arguments to be converted via cygpath
+    ROOTDIRSRAW=`find -L / -maxdepth 1 -mindepth 1 -type d 2>/dev/null`
+    SEP=""
+    for dir in $ROOTDIRSRAW ; do
+        ROOTDIRS="$ROOTDIRS$SEP$dir"
+        SEP="|"
+    done
+    OURCYGPATTERN="(^($ROOTDIRS))"
+    # Add a user-defined pattern to the cygpath arguments
+    if [ "$GRADLE_CYGPATTERN" != "" ] ; then
+        OURCYGPATTERN="$OURCYGPATTERN|($GRADLE_CYGPATTERN)"
+    fi
+    # Now convert the arguments - kludge to limit ourselves to /bin/sh
+    i=0
+    for arg in "$@" ; do
+        CHECK=`echo "$arg"|egrep -c "$OURCYGPATTERN" -`
+        CHECK2=`echo "$arg"|egrep -c "^-"`                                 ### Determine if an option
+
+        if [ $CHECK -ne 0 ] && [ $CHECK2 -eq 0 ] ; then                    ### Added a condition
+            eval `echo args$i`=`cygpath --path --ignore --mixed "$arg"`
+        else
+            eval `echo args$i`="\"$arg\""
+        fi
+        i=`expr $i + 1`
+    done
+    case $i in
+        0) set -- ;;
+        1) set -- "$args0" ;;
+        2) set -- "$args0" "$args1" ;;
+        3) set -- "$args0" "$args1" "$args2" ;;
+        4) set -- "$args0" "$args1" "$args2" "$args3" ;;
+        5) set -- "$args0" "$args1" "$args2" "$args3" "$args4" ;;
+        6) set -- "$args0" "$args1" "$args2" "$args3" "$args4" "$args5" ;;
+        7) set -- "$args0" "$args1" "$args2" "$args3" "$args4" "$args5" "$args6" ;;
+        8) set -- "$args0" "$args1" "$args2" "$args3" "$args4" "$args5" "$args6" "$args7" ;;
+        9) set -- "$args0" "$args1" "$args2" "$args3" "$args4" "$args5" "$args6" "$args7" "$args8" ;;
+    esac
+fi
+
+# Escape application args
+save () {
+    for i do printf %s\\n "$i" | sed "s/'/'\\\\''/g;1s/^/'/;\$s/\$/' \\\\/" ; done
+    echo " "
+}
+APP_ARGS=`save "$@"`
+
+# Collect all arguments for the java command, following the shell quoting and substitution rules
+eval set -- $DEFAULT_JVM_OPTS $JAVA_OPTS $GRADLE_OPTS "\"-Dorg.gradle.appname=$APP_BASE_NAME\"" -classpath "\"$CLASSPATH\"" org.gradle.wrapper.GradleWrapperMain "$APP_ARGS"
+
+exec "$JAVACMD" "$@"

gradlew.bat

+@rem
+@rem Copyright 2015 the original author or authors.
+@rem
+@rem Licensed under the Apache License, Version 2.0 (the "License");
+@rem you may not use this file except in compliance with the License.
+@rem You may obtain a copy of the License at
+@rem
+@rem      https://www.apache.org/licenses/LICENSE-2.0
+@rem
+@rem Unless required by applicable law or agreed to in writing, software
+@rem distributed under the License is distributed on an "AS IS" BASIS,
+@rem WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+@rem See the License for the specific language governing permissions and
+@rem limitations under the License.
+@rem
+
+@if "%DEBUG%" == "" @echo off
+@rem ##########################################################################
+@rem
+@rem  Gradle startup script for Windows
+@rem
+@rem ##########################################################################
+
+@rem Set local scope for the variables with windows NT shell
+if "%OS%"=="Windows_NT" setlocal
+
+set DIRNAME=%~dp0
+if "%DIRNAME%" == "" set DIRNAME=.
+set APP_BASE_NAME=%~n0
+set APP_HOME=%DIRNAME%
+
+@rem Resolve any "." and ".." in APP_HOME to make it shorter.
+for %%i in ("%APP_HOME%") do set APP_HOME=%%~fi
+
+@rem Add default JVM options here. You can also use JAVA_OPTS and GRADLE_OPTS to pass JVM options to this script.
+set DEFAULT_JVM_OPTS="-Xmx64m" "-Xms64m"
+
+@rem Find java.exe
+if defined JAVA_HOME goto findJavaFromJavaHome
+
+set JAVA_EXE=java.exe
+%JAVA_EXE% -version >NUL 2>&1
+if "%ERRORLEVEL%" == "0" goto init
+
+echo.
+echo ERROR: JAVA_HOME is not set and no 'java' command could be found in your PATH.
+echo.
+echo Please set the JAVA_HOME variable in your environment to match the
+echo location of your Java installation.
+
+goto fail
+
+:findJavaFromJavaHome
+set JAVA_HOME=%JAVA_HOME:"=%
+set JAVA_EXE=%JAVA_HOME%/bin/java.exe
+
+if exist "%JAVA_EXE%" goto init
+
+echo.
+echo ERROR: JAVA_HOME is set to an invalid directory: %JAVA_HOME%
+echo.
+echo Please set the JAVA_HOME variable in your environment to match the
+echo location of your Java installation.
+
+goto fail
+
+:init
+@rem Get command-line arguments, handling Windows variants
+
+if not "%OS%" == "Windows_NT" goto win9xME_args
+
+:win9xME_args
+@rem Slurp the command line arguments.
+set CMD_LINE_ARGS=
+set _SKIP=2
+
+:win9xME_args_slurp
+if "x%~1" == "x" goto execute
+
+set CMD_LINE_ARGS=%*
+
+:execute
+@rem Setup the command line
+
+set CLASSPATH=%APP_HOME%\gradle\wrapper\gradle-wrapper.jar
+
+
+@rem Execute Gradle
+"%JAVA_EXE%" %DEFAULT_JVM_OPTS% %JAVA_OPTS% %GRADLE_OPTS% "-Dorg.gradle.appname=%APP_BASE_NAME%" -classpath "%CLASSPATH%" org.gradle.wrapper.GradleWrapperMain %CMD_LINE_ARGS%
+
+:end
+@rem End local scope for the variables with windows NT shell
+if "%ERRORLEVEL%"=="0" goto mainEnd
+
+:fail
+rem Set variable GRADLE_EXIT_CONSOLE if you need the _script_ return code instead of
+rem the _cmd.exe /c_ return code!
+if  not "" == "%GRADLE_EXIT_CONSOLE%" exit 1
+exit /b 1
+
+:mainEnd
+if "%OS%"=="Windows_NT" endlocal
+
+:omega

settings.gradle

+rootProject.name = 'avatar'

src/main/java/au/com/tpic/avatar/AvatarApplication.java

+package au.com.tpic.avatar;
+
+import org.springframework.boot.SpringApplication;
+import org.springframework.boot.autoconfigure.SpringBootApplication;
+
+@SpringBootApplication
+public class AvatarApplication {
+
+	public static void main(String[] args) {
+		SpringApplication.run(AvatarApplication.class, args);
+	}
+
+}

src/main/java/au/com/tpic/avatar/configuration/AvatarServiceProperites.java

+package au.com.tpic.avatar.configuration;
+
+import lombok.Data;
+import org.springframework.boot.context.properties.ConfigurationProperties;
+import org.springframework.context.annotation.Configuration;
+
+import java.nio.file.Path;
+
+@Configuration
+@ConfigurationProperties(value = "avatar")
+@Data
+public class AvatarServiceProperites {
+    private Path directory;
+}

src/main/java/au/com/tpic/avatar/services/AvatarService.java

+package au.com.tpic.avatar.services;
+
+import au.com.tpic.avatar.configuration.AvatarServiceProperites;
+import org.springframework.stereotype.Service;
+import org.springframework.util.DigestUtils;
+
+import javax.imageio.ImageIO;
+import java.awt.*;
+import java.awt.geom.AffineTransform;
+import java.awt.image.AffineTransformOp;
+import java.awt.image.BufferedImage;
+import java.awt.image.WritableRaster;
+import java.io.ByteArrayOutputStream;
+import java.io.IOException;
+import java.nio.file.Files;
+import java.nio.file.Path;
+import java.util.HashMap;
+import java.util.List;
+import java.util.stream.Stream;
+
+@Service
+public class AvatarService {
+
+    private final HashMap<String, Path> fileList;
+
+    public AvatarService(AvatarServiceProperites properites) throws IOException {
+        Stream<Path> avatars = Files.walk(properites.getDirectory());
+        this.fileList = new HashMap<>();
+        avatars.filter(this::correctFormat).forEach(path -> this.fileList.put(getHash(path), path));
+    }
+
+    public byte[] getAvatar(String hash, String size) throws IOException {
+        try {
+            hash = hash.toLowerCase();
+            ByteArrayOutputStream baos = new ByteArrayOutputStream();
+            BufferedImage image = (fileList.containsKey(hash)) ? readImageToSize(fileList.get(hash), Integer.parseInt(size)) : generateIdenticons(hash, Integer.parseInt(size));
+            ImageIO.write(image, "jpg", baos);
+            return baos.toByteArray();
+        } catch (Exception ignored) {
+            return getClass().getClassLoader().getResourceAsStream("default.jpg").readAllBytes();
+        }
+    }
+
+    public static BufferedImage generateIdenticons(String text, int size) {
+        int width = 5, height = 5;
+
+        byte[] hash = text.getBytes();
+
+        BufferedImage identicon = new BufferedImage(width, height, BufferedImage.TYPE_INT_RGB);
+        WritableRaster raster = identicon.getRaster();
+
+        int[] background = new int[]{255, 255, 255};
+        int[] foreground = new int[]{hash[0] & 255, hash[3] & 255, hash[6] & 255};
+
+        for (int x = 0; x < width; x++) {
+            //Enforce horizontal symmetry
+            int i = x < 3 ? x : 4 - x;
+            for (int y = 0; y < height; y++) {
+                int[] pixelColor;
+                //toggle pixels based on bit being on/off
+                if ((hash[i] >> y & 1) == 1)
+                    pixelColor = foreground;
+                else
+                    pixelColor = background;
+                raster.setPixel(x, y, pixelColor);
+            }
+        }
+
+        BufferedImage finalImage = new BufferedImage(size, size, BufferedImage.TYPE_INT_RGB);
+
+        //Scale image to the size you want
+        AffineTransform at = new AffineTransform();
+        at.scale(size / width, size / height);
+        AffineTransformOp op = new AffineTransformOp(at, AffineTransformOp.TYPE_NEAREST_NEIGHBOR);
+        finalImage = op.filter(identicon, finalImage);
+
+        return finalImage;
+    }
+
+    private BufferedImage readImageToSize(Path image, int size) throws IOException {
+        BufferedImage inputImage = ImageIO.read(image.toFile());
+        int newHeight = inputImage.getHeight() / inputImage.getWidth() * size;
+        BufferedImage outputImage = new BufferedImage(size, newHeight, BufferedImage.TYPE_INT_RGB);
+        Graphics2D graphics2D = outputImage.createGraphics();
+        graphics2D.drawImage(inputImage, 0, 0, size, newHeight, null);
+        return outputImage;
+    }
+
+    private String getHash(Path path) {
+        String filename = com.google.common.io.Files.getNameWithoutExtension(path.getFileName().toString());
+        return DigestUtils.md5DigestAsHex(filename.getBytes());
+    }
+
+    private boolean correctFormat(Path path) {
+        List<String> accepted = List.of("jpg", "jpeg", "jfif", "png", "gif");
+        String extension = com.google.common.io.Files.getFileExtension(path.getFileName().toString());
+        return accepted.contains(extension.toLowerCase());
+    }
+
+
+}

src/main/java/au/com/tpic/avatar/web/AvatarController.java

+package au.com.tpic.avatar.web;
+
+import au.com.tpic.avatar.services.AvatarService;
+import org.springframework.beans.factory.annotation.Autowired;
+import org.springframework.http.MediaType;
+import org.springframework.web.bind.annotation.*;
+
+import java.io.IOException;
+
+@RestController
+@RequestMapping("/avatar")
+public class AvatarController {
+
+    @Autowired
+    private AvatarService service;
+
+    @GetMapping(produces = MediaType.IMAGE_JPEG_VALUE)
+    public byte[] getDefaultAvatar(@RequestParam(value = "s", required = false, defaultValue = "200") String size) throws IOException {
+        return service.getAvatar(null, size);
+    }
+
+    @GetMapping(value = "{hash}", produces = MediaType.IMAGE_JPEG_VALUE)
+    public byte[] getAvatar(@PathVariable String hash, @RequestParam(value = "s", required = false, defaultValue = "200") String size) throws IOException {
+        return service.getAvatar(hash, size);
+    }
+}

src/main/resources/application.yml

+avatar:
+  directory: /opt/avatar
+server:
+  http2:
+    enabled: true
+  compression:
+    enabled: true
+  port: 8888
\ No newline at end of file

src/test/java/au/com/tpic/avatar/AvatarApplicationTests.java

+package au.com.tpic.avatar;
+
+import org.junit.jupiter.api.Test;
+import org.springframework.boot.test.context.SpringBootTest;
+
+@SpringBootTest
+class AvatarApplicationTests {
+
+    @Test
+    void contextLoads() {
+    }
+
+}