Add "configuration" object to response of /api/v1/instance endpoint

CHANGELOG.md

@@ -11,6 +11,7 @@ The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.0.0/).
 - Added `/api/v1/accounts/lookup` Mastodon API endpoint.
 - Implemented activity delivery queue.
 - Started to keep track of unreachable actors.
+- Added `configuration` object to response of `/api/v1/instance` endpoint.
 
 ### Changed
 
@@ -18,6 +19,10 @@ The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.0.0/).
 - Limited the number of requests made during the processing of a thread.
 - Limited the number of media files that can be attached to a post.
 
+### Deprecated
+
+- Deprecated `post_character_limit` property in `/api/v1/instance` response.
+
 ### Removed
 
 - Removed ability to upload non-images using `/api/v1/media` endpoint.

docs/openapi.yaml

@@ -1394,6 +1394,36 @@ components:
             domain_count:
               description: Domains federated with this instance.
               type: integer
+        configuration:
+          description: Configured values and limits for this instance.
+          type: object
+          properties:
+            statuses:
+              description: Limits related to authoring posts.
+              type: object
+              properties:
+                max_characters:
+                  description: The maximum number of allowed characters per post.
+                  type: integer
+                  example: 5000
+                max_media_attachments:
+                  description: The maximum number of media attachments that can be added to a post.
+                  type: integer
+                  example: 15
+            media_attachments:
+              description: Limits realted to uploading attachments.
+              type: object
+              properties:
+                supported_mime_types:
+                  description: Contains MIME types that can be uploaded.
+                  type: array
+                  items:
+                    type: string
+                    example: 'image/png'
+                image_size_limit:
+                  description: The maximum size of any uploaded image, in bytes.
+                  type: integer
+                  example: 5242880
         login_message:
           description: Login message for signer.
           type: string

src/mastodon_api/instance/types.rs

@@ -3,8 +3,15 @@ use serde_json::{to_value, Value};
 
 use crate::config::{BlockchainConfig, Config};
 use crate::ethereum::contracts::ContractSet;
-use crate::mastodon_api::MASTODON_API_VERSION;
-use crate::utils::markdown::markdown_to_html;
+use crate::mastodon_api::{
+    MASTODON_API_VERSION,
+    uploads::UPLOAD_MAX_SIZE,
+};
+use crate::models::posts::validators::ATTACHMENTS_MAX_NUM;
+use crate::utils::{
+    files::SUPPORTED_MEDIA_TYPES,
+    markdown::markdown_to_html,
+};
 
 #[derive(Serialize)]
 struct InstanceStats {
@@ -13,6 +20,24 @@ struct InstanceStats {
     domain_count: i64,
 }
 
+#[derive(Serialize)]
+struct InstanceStatusLimits {
+    max_characters: usize,
+    max_media_attachments: usize,
+}
+
+#[derive(Serialize)]
+struct InstanceMediaLimits {
+    supported_mime_types: [&'static str; 4],
+    image_size_limit: usize,
+}
+
+#[derive(Serialize)]
+struct InstanceConfiguration {
+    statuses: InstanceStatusLimits,
+    media_attachments: InstanceMediaLimits,
+}
+
 #[derive(Serialize)]
 struct BlockchainFeatures {
     gate: bool,
@@ -28,6 +53,7 @@ struct BlockchainInfo {
     features: BlockchainFeatures,
 }
 
+/// https://docs.joinmastodon.org/entities/V1_Instance/
 #[derive(Serialize)]
 pub struct InstanceInfo {
     uri: String,
@@ -38,6 +64,7 @@ pub struct InstanceInfo {
     version: String,
     registrations: bool,
     stats: InstanceStats,
+    configuration: InstanceConfiguration,
 
     login_message: String,
     post_character_limit: usize,
@@ -116,6 +143,16 @@ impl InstanceInfo {
                 status_count: post_count,
                 domain_count: peer_count,
             },
+            configuration: InstanceConfiguration {
+                statuses: InstanceStatusLimits {
+                    max_characters: config.post_character_limit,
+                    max_media_attachments: ATTACHMENTS_MAX_NUM,
+                },
+                media_attachments: InstanceMediaLimits {
+                    supported_mime_types: SUPPORTED_MEDIA_TYPES,
+                    image_size_limit: UPLOAD_MAX_SIZE,
+                },
+            },
             login_message: config.login_message.clone(),
             post_character_limit: config.post_character_limit,
             blockchains: blockchains,

src/mastodon_api/instance/views.rs

@@ -11,6 +11,7 @@ use crate::models::{
 };
 use super::types::InstanceInfo;
 
+/// https://docs.joinmastodon.org/methods/instance/#v1
 #[get("")]
 async fn instance_view(
     config: web::Data<Config>,