Allow calling follow/unfollow API methods multiple times

For compatibility with Mastodon.

docs/openapi.yaml

@@ -204,6 +204,38 @@ paths:
                   $ref: '#/components/schemas/Account'
         404:
           description: Profile not found
+  /api/v1/accounts/{account_id}/follow:
+    post:
+      summary: Follow the given actor.
+      security:
+        - tokenAuth: []
+      parameters:
+        - $ref: '#/components/parameters/account_id'
+      responses:
+        200:
+          description: Successfully followed, or actor was already followed
+          content:
+            application/json:
+              schema:
+                $ref: '#/components/schemas/Relationship'
+        404:
+          description: Profile not found
+  /api/v1/accounts/{account_id}/unfollow:
+    post:
+      summary: Unfollow the given actor.
+      security:
+        - tokenAuth: []
+      parameters:
+        - $ref: '#/components/parameters/account_id'
+      responses:
+        200:
+          description: Successfully unfollowed, or actor was already not followed
+          content:
+            application/json:
+              schema:
+                $ref: '#/components/schemas/Relationship'
+        404:
+          description: Profile not found
   /api/v1/statuses/{status_id}:
     delete:
       summary: Delete post
@@ -330,6 +362,10 @@ paths:
                   $ref: '#/components/schemas/Status'
 
 components:
+  securitySchemes:
+    tokenAuth:
+      type: http
+      scheme: bearer
   parameters:
     account_id:
       name: account_id
@@ -367,6 +403,22 @@ components:
           description: Ethereum wallet address.
           type: string
           example: '0xd8da6bf...'
+    Relationship:
+      type: object
+      properties:
+        id:
+          description: The account id.
+          type: string
+          format: uuid
+        following:
+          description: Are you following this user?
+          type: boolean
+        followed_by:
+          description: Are you followed by this user?
+          type: boolean
+        requested:
+          description: Do you have a pending follow request for this user?
+          type: boolean
     Status:
       type: object
       properties:

src/mastodon_api/accounts/views.rs

@@ -12,7 +12,7 @@ use crate::activitypub::actor::Actor;
 use crate::activitypub::deliverer::deliver_activity;
 use crate::config::Config;
 use crate::database::{Pool, get_database_client};
-use crate::errors::{HttpError, ValidationError};
+use crate::errors::{DatabaseError, HttpError, ValidationError};
 use crate::ethereum::gate::is_allowed_user;
 use crate::mastodon_api::oauth::auth::get_current_user;
 use crate::models::posts::helpers::{
@@ -209,16 +209,25 @@ async fn follow_account(
     let target = get_profile_by_id(db_client, &account_id).await?;
     if let Some(remote_actor) = target.actor_json {
         // Remote follow
-        let request = create_follow_request(db_client, &current_user.id, &target.id).await?;
-        let activity = create_activity_follow(
-            &config.instance_url(),
-            &current_user.profile,
-            &request.id,
-            &remote_actor.id,
-        );
-        deliver_activity(&config, &current_user, activity, vec![remote_actor]);
+        match create_follow_request(db_client, &current_user.id, &target.id).await {
+            Ok(request) => {
+                let activity = create_activity_follow(
+                    &config.instance_url(),
+                    &current_user.profile,
+                    &request.id,
+                    &remote_actor.id,
+                );
+                deliver_activity(&config, &current_user, activity, vec![remote_actor]);
+            },
+            Err(DatabaseError::AlreadyExists(_)) => (), // already following
+            Err(other_error) => return Err(other_error.into()),
+        };
     } else {
-        follow(db_client, &current_user.id, &target.id).await?;
+        match follow(db_client, &current_user.id, &target.id).await {
+            Ok(_) => (),
+            Err(DatabaseError::AlreadyExists(_)) => (), // already following
+            Err(other_error) => return Err(other_error.into()),
+        };
     };
     let relationship = get_relationship(
         db_client,
@@ -240,26 +249,35 @@ async fn unfollow_account(
     let target = get_profile_by_id(db_client, &account_id).await?;
     if let Some(remote_actor) = target.actor_json {
         // Remote follow
-        let follow_request = get_follow_request_by_path(
+        match get_follow_request_by_path(
             db_client,
             &current_user.id,
             &target.id,
-        ).await?;
-        unfollow(
-            db_client,
-            &current_user.id,
-            &target.id,
-        ).await?;
-        // Federate
-        let activity = create_activity_undo_follow(
-            &config.instance_url(),
-            &current_user.profile,
-            &follow_request.id,
-            &remote_actor.id,
-        );
-        deliver_activity(&config, &current_user, activity, vec![remote_actor]);
+        ).await {
+            Ok(follow_request) => {
+                unfollow(
+                    db_client,
+                    &current_user.id,
+                    &target.id,
+                ).await?;
+                // Federate
+                let activity = create_activity_undo_follow(
+                    &config.instance_url(),
+                    &current_user.profile,
+                    &follow_request.id,
+                    &remote_actor.id,
+                );
+                deliver_activity(&config, &current_user, activity, vec![remote_actor]);
+            },
+            Err(DatabaseError::NotFound(_)) => (), // not following
+            Err(other_error) => return Err(other_error.into()),
+        };
     } else {
-        unfollow(db_client, &current_user.id, &target.id).await?;
+        match unfollow(db_client, &current_user.id, &target.id).await {
+            Ok(_) => (),
+            Err(DatabaseError::NotFound(_)) => (), // not following
+            Err(other_error) => return Err(other_error.into()),
+        };
     };
     let relationship = get_relationship(
         db_client,

src/models/relationships/queries.rs

@@ -161,7 +161,7 @@ pub async fn create_follow_request(
             &request.target_id,
             &request.request_status,
         ],
-    ).await?;
+    ).await.map_err(catch_unique_violation("follow request"))?;
     Ok(request)
 }