Add API method for getting authorization of paid subscription setup transaction

docs/openapi.yaml

@@ -87,6 +87,20 @@ paths:
                 $ref: '#/components/schemas/Account'
         400:
           description: Invalid user data
+  /api/v1/accounts/authorize_subscription:
+    get:
+      summary: Get authorization for setting up paid subscription.
+      responses:
+        200:
+          description: Signature created
+          content:
+            application/json:
+              schema:
+                $ref: '#/components/schemas/Signature'
+        403:
+          description: User's wallet address is not known
+        418:
+          description: Blockchain integration is not enabled
   /api/v1/accounts/relationships:
     get:
       summary: Find out whether a given actor is followed, blocked, muted, etc.
@@ -431,24 +445,13 @@ paths:
           content:
             application/json:
               schema:
-                type: object
-                properties:
-                  v:
-                    type: integer
-                    format: int64
-                    example: 27
-                  r:
-                    type: string
-                    example: '6f61670e67bf72...'
-                  s:
-                    type: string
-                    example: '6a5cb313907cd3...'
+                $ref: '#/components/schemas/Signature'
         403:
           description: Post does not belong to user, is not public or not saved to IPFS, or user's wallet address is not known
         404:
           description: Post not found
         418:
-          description: Ethereum integration is not enabled
+          description: Blockchain integration is not enabled
   /api/v1/statuses/{status_id}/token_minted:
     post:
       summary: Register transaction that mints a token
@@ -648,6 +651,19 @@ components:
         requested:
           description: Do you have a pending follow request for this user?
           type: boolean
+    Signature:
+      type: object
+      properties:
+        v:
+          type: integer
+          format: int64
+          example: 27
+        r:
+          type: string
+          example: '6f61670e67bf72...'
+        s:
+          type: string
+          example: '6a5cb313907cd3...'
     Status:
       type: object
       properties:

src/ethereum/mod.rs

@@ -4,4 +4,5 @@ mod errors;
 pub mod gate;
 pub mod nft;
 pub mod signatures;
+pub mod subscriptions;
 pub mod utils;

src/ethereum/subscriptions.rs

@@ -0,0 +1,20 @@
+use crate::config::BlockchainConfig;
+use super::errors::EthereumError;
+use super::signatures::{sign_contract_call, CallArgs, SignatureData};
+use super::utils::parse_address;
+
+pub fn create_subscription_signature(
+    blockchain_config: &BlockchainConfig,
+    user_address: &str,
+) -> Result<SignatureData, EthereumError> {
+    let user_address = parse_address(user_address)?;
+    let call_args: CallArgs = vec![Box::new(user_address)];
+    let signature = sign_contract_call(
+        &blockchain_config.signing_key,
+        blockchain_config.ethereum_chain_id(),
+        &blockchain_config.contract_address,
+        "configureSubscription",
+        call_args,
+    )?;
+    Ok(signature)
+}

src/mastodon_api/accounts/views.rs

@@ -14,6 +14,7 @@ use crate::config::Config;
 use crate::database::{Pool, get_database_client};
 use crate::errors::{DatabaseError, HttpError, ValidationError};
 use crate::ethereum::gate::is_allowed_user;
+use crate::ethereum::subscriptions::create_subscription_signature;
 use crate::mastodon_api::oauth::auth::get_current_user;
 use crate::models::posts::helpers::{
     get_actions_for_posts,
@@ -171,6 +172,25 @@ async fn update_credentials(
     Ok(HttpResponse::Ok().json(account))
 }
 
+#[get("/authorize_subscription")]
+async fn authorize_subscription(
+    auth: BearerAuth,
+    config: web::Data<Config>,
+    db_pool: web::Data<Pool>,
+) -> Result<HttpResponse, HttpError> {
+    let db_client = &**get_database_client(&db_pool).await?;
+    let current_user = get_current_user(db_client, auth.token()).await?;
+    let blockchain_config = config.blockchain.as_ref()
+        .ok_or(HttpError::NotSupported)?;
+    let wallet_address = current_user.wallet_address
+        .ok_or(HttpError::PermissionError)?;
+    let signature = create_subscription_signature(
+        blockchain_config,
+        &wallet_address,
+    ).map_err(|_| HttpError::InternalError)?;
+    Ok(HttpResponse::Ok().json(signature))
+}
+
 // TODO: actix currently doesn't support parameter arrays
 // https://github.com/actix/actix-web/issues/2044
 #[derive(Deserialize)]
@@ -384,6 +404,7 @@ pub fn account_api_scope() -> Scope {
         .service(get_relationships_view)
         .service(verify_credentials)
         .service(update_credentials)
+        .service(authorize_subscription)
         // Routes with account ID
         .service(get_account)
         .service(follow_account)