Java-Discord#60 working implementation for very basic gist links. Doe…

…s not work yet if a specific file in a multifile gist is given.

build.gradle

@@ -30,6 +30,11 @@ dependencies {
     // H2 Database
     implementation group: 'com.h2database', name: 'h2', version: '1.4.200'
 
+    // Retrofit
+    implementation group: 'com.squareup.retrofit2', name: 'retrofit', version: '2.9.0'
+    implementation group: 'com.squareup.retrofit2', name: 'converter-jackson', version: '2.9.0'
+
+
     // Lombok Annotations
     compileOnly 'org.projectlombok:lombok:1.18.20'
     annotationProcessor 'org.projectlombok:lombok:1.18.20'

src/main/java/com/javadiscord/javabot/Bot.java

@@ -96,7 +96,8 @@ private static void addEventListeners(JDA jda) {
                 new StarboardListener(),
                 new InteractionListener(),
                 new HelpChannelListener(),
-                new ShareKnowledgeVoteListener()
+                new ShareKnowledgeVoteListener(),
+                new GistListener()
         );
     }
 }

src/main/java/com/javadiscord/javabot/events/GistListener.java

@@ -0,0 +1,70 @@
+package com.javadiscord.javabot.events;
+
+import com.javadiscord.javabot.external_apis.github.GistResponse;
+import com.javadiscord.javabot.external_apis.github.GithubService;
+import net.dv8tion.jda.api.events.message.guild.GuildMessageReceivedEvent;
+import net.dv8tion.jda.api.hooks.ListenerAdapter;
+import org.jetbrains.annotations.NotNull;
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+import retrofit2.Call;
+import retrofit2.Callback;
+import retrofit2.Response;
+import retrofit2.Retrofit;
+import retrofit2.converter.jackson.JacksonConverterFactory;
+
+import java.util.regex.Matcher;
+import java.util.regex.Pattern;
+
+public class GistListener extends ListenerAdapter {
+
+    private static String BASIC_GIST_PATTERN_STRING = ".*https://gist\\.github\\.com/.+?(?=/)/(.+?(?=#|\\s))";
+    private static Pattern BASIC_GIST_PATTERN = Pattern.compile(BASIC_GIST_PATTERN_STRING);
+    private GithubService service;
+    private static int SIZE_LIMIT = 2000;
+    private static final Logger log = LoggerFactory.getLogger(GistListener.class);
+
+
+    public GistListener() {
+        Retrofit retrofit = new Retrofit.Builder()
+                .baseUrl("https://api.github.com/")
+                .addConverterFactory(JacksonConverterFactory.create())
+                .build();
+
+        service = retrofit.create(GithubService.class);
+    }
+
+    @Override
+    public void onGuildMessageReceived(@NotNull GuildMessageReceivedEvent event) {
+        if (event.getAuthor().isBot()) return;
+        Matcher matcher = BASIC_GIST_PATTERN.matcher(event.getMessage().getContentRaw());
+
+        if (matcher.find()) {
+            service.getGistInformation(matcher.group(1)).enqueue(new Callback<>() {
+                @Override
+                public void onResponse(@NotNull Call<GistResponse> call, @NotNull Response<GistResponse> response) {
+                    GistResponse result = response.body();
+                    if (result == null || result.getFiles().size() != 1) return;
+                    result.getFiles().values().forEach(file -> {
+                        if (file.getSize() <= SIZE_LIMIT) {
+                            String message = constructMessage(file.getContent(), file.getLanguage());
+                            event.getChannel().sendMessage(message).queue();
+                        }
+                    });
+                }
+
+
+                @Override
+                public void onFailure(@NotNull Call<GistResponse> call, @NotNull Throwable t) {
+                    log.error("Unable to complete/parse Gist api call", t);
+                }
+            });
+        }
+
+
+    }
+
+    public String constructMessage(String content, String language) {
+        return "```" + language + "\n" + content + "```";
+    }
+}

src/main/java/com/javadiscord/javabot/external_apis/github/File.java

@@ -0,0 +1,53 @@
+package com.javadiscord.javabot.external_apis.github;
+
+import com.fasterxml.jackson.annotation.JsonIgnoreProperties;
+
+@JsonIgnoreProperties(ignoreUnknown = true)
+public class File {
+    private String language;
+    private String raw_url;
+    private Integer size;
+    private String content;
+
+    @Override
+    public String toString() {
+        return "File{" +
+                "language='" + language + '\'' +
+                ", rawURL='" + raw_url + '\'' +
+                ", size=" + size +
+                ", content='" + content + '\'' +
+                '}';
+    }
+
+    public String getLanguage() {
+        return language;
+    }
+
+    public void setLanguage(String language) {
+        this.language = language;
+    }
+
+    public String getRaw_url() {
+        return raw_url;
+    }
+
+    public void setRaw_url(String raw_url) {
+        this.raw_url = raw_url;
+    }
+
+    public int getSize() {
+        return size;
+    }
+
+    public void setSize(int size) {
+        this.size = size;
+    }
+
+    public String getContent() {
+        return content;
+    }
+
+    public void setContent(String content) {
+        this.content = content;
+    }
+}

src/main/java/com/javadiscord/javabot/external_apis/github/GistResponse.java

@@ -0,0 +1,35 @@
+package com.javadiscord.javabot.external_apis.github;
+
+import com.fasterxml.jackson.annotation.JsonIgnoreProperties;
+
+import java.util.Map;
+
+@JsonIgnoreProperties(ignoreUnknown = true)
+public class GistResponse {
+    private String url;
+    private Map<String, File> files;
+
+    @Override
+    public String toString() {
+        return "GistResponse{" +
+                "url='" + url + '\'' +
+                ", files=" + files +
+                '}';
+    }
+
+    public String getUrl() {
+        return url;
+    }
+
+    public void setUrl(String url) {
+        this.url = url;
+    }
+
+    public Map<String, File> getFiles() {
+        return files;
+    }
+
+    public void setFiles(Map<String, File> files) {
+        this.files = files;
+    }
+}

src/main/java/com/javadiscord/javabot/external_apis/github/GithubService.java

@@ -0,0 +1,11 @@
+package com.javadiscord.javabot.external_apis.github;
+
+
+import retrofit2.Call;
+import retrofit2.http.GET;
+import retrofit2.http.Path;
+
+public interface GithubService {
+    @GET("gists/{gistID}")
+    Call<GistResponse> getGistInformation(@Path("gistID") String gistID);
+}