From ddaa3a5a0623742bb52300bef87d2598ddb1e581 Mon Sep 17 00:00:00 2001
From: Pierre HUBERT <pierre.git@communiquons.org>
Date: Sat, 4 Jan 2020 12:04:14 +0100
Subject: [PATCH] Can get information about a single post

---
 src/controllers/PostsController.ts | 13 +++++++++
 src/controllers/Routes.ts          |  2 ++
 src/entities/RequestHandler.ts     | 33 ++++++++++++++++++++++
 src/helpers/PostsHelper.ts         | 45 ++++++++++++++++++++++++++++++
 4 files changed, 93 insertions(+)

diff --git a/src/controllers/PostsController.ts b/src/controllers/PostsController.ts
index 0fe50dc..8d967ed 100644
--- a/src/controllers/PostsController.ts
+++ b/src/controllers/PostsController.ts
@@ -78,6 +78,19 @@ export class PostsController {
 		await this.SendMultiplePosts(h, posts);
 	}
 
+	/**
+	 * Get information about a single post
+	 * 
+	 * @param h Request handler
+	 */
+	public static async GetSingle(h: RequestHandler) {
+		const postID = await h.postPostIDWithAccess("postID");
+
+		const post = await PostsHelper.GetSingle(postID);
+
+		h.send(await this.PostToAPI(h, post));
+	}
+
 
 	/**
 	 * Send multiple posts to the API
diff --git a/src/controllers/Routes.ts b/src/controllers/Routes.ts
index 8752a40..0b41584 100644
--- a/src/controllers/Routes.ts
+++ b/src/controllers/Routes.ts
@@ -190,6 +190,8 @@ export const Routes : Route[] = [
 
 	{path: "/posts/get_latest", cb: (h) => PostsController.GetLatest(h)},
 
+	{path: "/posts/get_single", cb: (h) => PostsController.GetSingle(h), needLogin: false},
+
 
 
 	// Notifications controller
diff --git a/src/entities/RequestHandler.ts b/src/entities/RequestHandler.ts
index 9948aef..d639a49 100644
--- a/src/entities/RequestHandler.ts
+++ b/src/entities/RequestHandler.ts
@@ -11,6 +11,8 @@ import { GroupsAccessLevel } from "./Group";
 import { GroupsHelper } from "../helpers/GroupsHelper";
 import { checkVirtualDirectory } from "../utils/VirtualDirsUtils";
 import { FriendsHelper } from "../helpers/FriendsHelper";
+import { PostsHelper } from "../helpers/PostsHelper";
+import { PostAccessLevel } from "./Post";
 
 /**
  * Response to a request
@@ -274,6 +276,37 @@ export class RequestHandler {
 		return groupID;
 	}
 
+	/**
+	 * Get the ID of post included in a POST request
+	 * 
+	 * @param name The name of the POST field containing the id of the target post
+	 */
+	public async postPostID(name: string) : Promise<number> {
+		const postID = this.postInt(name);
+
+		if(postID < 1)
+			this.error(400, "Invalid post ID!");
+		
+		if(!await PostsHelper.Exists(postID))
+			this.error(404, "Specified post does not exists!");
+		
+		return postID;
+	}
+
+	/**
+	 * Get the ID of a post a user has access to
+	 * 
+	 * @param name The name of the POST field containing the ID of the target post
+	 */
+	public async postPostIDWithAccess(name: string) : Promise<number> {
+		const postID = await this.postPostID(name);
+
+		if(await PostsHelper.GetAccessLevelFromPostID(this.optionnalUserID, postID) == PostAccessLevel.NO_ACCESS)
+			this.error(401, "Your are not allowed to access this post information!");
+		
+		return postID;
+	}
+
 	/**
 	 * Get a virtual directory included in a POST request
 	 * 
diff --git a/src/helpers/PostsHelper.ts b/src/helpers/PostsHelper.ts
index 352ed96..714d049 100644
--- a/src/helpers/PostsHelper.ts
+++ b/src/helpers/PostsHelper.ts
@@ -230,6 +230,37 @@ export class PostsHelper {
 		return results.map((r) => this.DBToPost(r));
 	}
 
+	/**
+	 * Get information about a single post
+	 * 
+	 * @param postID Target post ID
+	 */
+	public static async GetSingle(postID: number) : Promise<Post> {
+		const row = await DatabaseHelper.QueryRow({
+			table: TABLE_NAME,
+			where: {
+				ID: postID
+			}
+		});
+
+		if(row == null)
+			throw new Error("Post " + postID + " not found!");
+		
+		return this.DBToPost(row);
+	}
+
+	/**
+	 * Get the access level of a user over a post
+	 * 
+	 * This is a convenience function
+	 * 
+	 * @param userID Target user ID
+	 * @param postID Target post ID
+	 */
+	public static async GetAccessLevelFromPostID(userID: number, postID: number) : Promise<PostAccessLevel> {
+		return await this.GetAccessLevel(userID, await this.GetSingle(postID));
+	}
+
 	/**
 	 * Get the access level of a user over a post
 	 * 
@@ -312,6 +343,20 @@ export class PostsHelper {
 		return !post.isUserPage || await UserHelper.AllowComments(post.userPageID);
 	}
 
+	/**
+	 * Check out whether a post exists or not
+	 * 
+	 * @param postID The id of the post to check
+	 */
+	public static async Exists(postID: number) : Promise<boolean> {
+		return await DatabaseHelper.Count({
+			table: TABLE_NAME,
+			where: {
+				ID: postID
+			}
+		}) > 0;
+	}
+
 	/**
 	 * Turn a database entry into a row object
 	 *