[FEAT] Expand code Link

github/GithubApp.ts

@@ -4,6 +4,7 @@ import {
     IConfigurationExtend,
     IHttp,
     ILogger,
+    IMessageExtender,
     IModify,
     IPersistence,
     IRead,
@@ -45,12 +46,40 @@ import { IJobContext } from "@rocket.chat/apps-engine/definition/scheduler";
 import { IRoom } from "@rocket.chat/apps-engine/definition/rooms";
 import { clearInteractionRoomData, getInteractionRoomData } from "./persistance/roomInteraction";
 import { GHCommand } from "./commands/GhCommand";
+import { IPreMessageSentExtend, IMessage } from "@rocket.chat/apps-engine/definition/messages";
+import { handleGitHubCodeSegmentLink } from "./handlers/GitHubCodeSegmentHandler";
+import { isGithubLink, hasGitHubCodeSegmentLink } from "./helpers/checkLinks";
 
-export class GithubApp extends App {
+export class GithubApp extends App implements IPreMessageSentExtend {
     constructor(info: IAppInfo, logger: ILogger, accessors: IAppAccessors) {
         super(info, logger, accessors);
     }
 
+    public async checkPreMessageSentExtend(
+        message: IMessage,
+        read: IRead,
+        http: IHttp
+    ): Promise<boolean> {
+        if (await isGithubLink(message)) {
+            return true;
+        }
+        return false;
+    }
+
+    public async executePreMessageSentExtend(
+        message: IMessage,
+        extend: IMessageExtender,
+        read: IRead,
+        http: IHttp,
+        persistence: IPersistence
+    ): Promise<IMessage> {
+
+        if (await hasGitHubCodeSegmentLink(message)) {
+            await handleGitHubCodeSegmentLink(message, read, http, message.sender, message.room, extend);
+        }
+        return extend.getMessage();
+    }
+
     public async authorizationCallback(
         token: IAuthData,
         user: IUser,

github/app.json

@@ -12,5 +12,7 @@
     "nameSlug": "github",
     "classFile": "GithubApp.ts",
     "description": "The ultimate app extending Rocket.Chat for all developers collaborating on Github",
-    "implements": []
+    "implements": [
+        "IPreMessageSentExtend"
+    ]
 }

github/enum/GitHubURL.ts

@@ -0,0 +1,5 @@
+export enum GitHubURLEnum {
+  PREFIX = "blob/",
+  HOST = "github.com",
+  RAW_HOST = "raw.githubusercontent.com",
+}

github/handlers/GitHubCodeSegmentHandler.ts

@@ -0,0 +1,69 @@
+import { IUser } from "@rocket.chat/apps-engine/definition/users";
+import { IHttp, IRead } from "@rocket.chat/apps-engine/definition/accessors";
+import { IMessage, IMessageAttachment } from "@rocket.chat/apps-engine/definition/messages";
+import { IRoom } from "@rocket.chat/apps-engine/definition/rooms";
+import { IMessageExtender } from "@rocket.chat/apps-engine/definition/accessors";
+import { TextObjectType } from "@rocket.chat/apps-engine/definition/uikit";
+import { GitHubURLEnum } from "../enum/GitHubURL";
+
+async function extractCodeSnippetFromURL(content: string, url: string): Promise<string> {
+    const lineRangeRegex: RegExp = /(?:L(\d+)+-L(\d+)|L(\d+))/;
+    const lineRangeMatch: RegExpMatchArray | null = url.match(lineRangeRegex);
+
+    if (lineRangeMatch) {
+        return extractCodeSnippetByLineRange(content, lineRangeMatch);
+    }
+
+    return "";
+}
+
+function extractCodeSnippetByLineRange(content: string, lineRangeMatch: RegExpMatchArray): string {
+    const [_, startLine, endLine, singleLine] = lineRangeMatch;
+
+    const lineOffset = singleLine ? parseInt(singleLine) : parseInt(startLine) - 1;
+    const lineCount = singleLine ? 1 : parseInt(endLine) - parseInt(startLine) + 1;
+
+    const linesRegex = `(?:.*\n){${lineOffset}}(.*(?:\n.*){${lineCount}})`;
+    const lines = new RegExp(linesRegex);
+    const match = content.match(lines);
+
+    return match?.[1] ?? "";
+}
+
+async function fetchGitHubContent(http: IHttp, modifiedUrl: string): Promise<string> {
+    const response: any = await http.get(modifiedUrl);
+    const { content } = response;
+    return content;
+}
+
+function buildCodeSnippetAttachment(codeSnippet: string, url: string): IMessageAttachment {
+    const attachment: IMessageAttachment = {
+        text: `\`\`\`\n${codeSnippet}\n\`\`\` \n[Show more...](${url})`,
+        type: TextObjectType.MARKDOWN,
+    };
+    return attachment;
+}
+
+export async function handleGitHubCodeSegmentLink(
+    message: IMessage,
+    read: IRead,
+    http: IHttp,
+    user: IUser,
+    room: IRoom,
+    extend: IMessageExtender
+) {
+    const urlRegex: RegExp = /\bhttps?:\/\/github\.com\/\S+\b/;
+    const messageText: string = message.text!;
+    const urlMatch: RegExpMatchArray | null = messageText.match(urlRegex);
+    const url: string | undefined = urlMatch?.[0];
+    let modifiedUrl: string = url?.replace(GitHubURLEnum.PREFIX, "")!;
+    modifiedUrl = modifiedUrl.replace(GitHubURLEnum.HOST, GitHubURLEnum.RAW_HOST);
+
+    const content: string = await fetchGitHubContent(http, modifiedUrl);
+    const codeSnippet = await extractCodeSnippetFromURL(content, modifiedUrl);
+
+    if (codeSnippet) {
+        const attachment: IMessageAttachment = buildCodeSnippetAttachment(codeSnippet, url!);
+        extend.addAttachment(attachment);
+    }
+}

github/helpers/checkLinks.ts

@@ -0,0 +1,19 @@
+import { IMessage } from "@rocket.chat/apps-engine/definition/messages";
+
+export async function hasGitHubCodeSegmentLink(message: IMessage): Promise<Boolean> {
+    let lineNo: RegExp =
+        /https?:\/\/github\.com\/[A-Za-z0-9_-]+\/[A-Za-z0-9_.-]+\/blob\/[A-Za-z0-9_-]+\/.+/;
+
+    if (lineNo.test(message.text!)) {
+        return true;
+    }
+    return false;
+}
+
+export async function isGithubLink(message: IMessage) {
+    let githubLink: RegExp = /(?:https?:\/\/)?(?:www\.)?github\.com\//;
+    if (githubLink.test(message.text!)) {
+        return true;
+    }
+    return false;
+}