Merge pull request #141 from xsnippet/plain-text-get-snippet

Add a GET /snippet/:id that allows to retrieve the raw content of a snippet as plain text

Author: malor

src/application.rs

@@ -70,6 +70,7 @@ pub fn create_app() -> Result<rocket::Rocket, Box<dyn Error>> {
         routes::snippets::create_snippet,
         routes::snippets::list_snippets,
         routes::snippets::get_snippet,
+        routes::snippets::get_raw_snippet,
         routes::syntaxes::get_syntaxes,
         routes::snippets::import_snippet,
     ];

src/errors.rs

@@ -1,12 +1,11 @@
-use std::convert::From;
-
 use rocket::http;
 use rocket::request::Request;
 use rocket::response::{self, Responder, Response};
+use rocket::Outcome;
 use serde::{ser::SerializeStruct, Serialize, Serializer};
 
 use crate::storage::StorageError;
-use crate::web::Output;
+use crate::web::{NegotiatedContentType, Output};
 
 /// All possible unsuccessful outcomes of an API request.
 ///
@@ -86,12 +85,22 @@ impl<'r> Responder<'r> for ApiError {
                 .status(http::Status::InternalServerError)
                 .ok()
         } else {
-            // otherwise, present the error in the requested data format
             let http_status = self.status();
             debug!("ApiError: {:?}", self);
-            Response::build_from(Output(self).respond_to(request)?)
+
+            match request.guard::<NegotiatedContentType>() {
+                // otherwise, present the error in the requested data format if content negotiation
+                // has succeeded
+                Outcome::Success(_) => Response::build_from(Output(self).respond_to(request)?)
+                    .status(http_status)
+                    .ok(),
+                // or as plain text if content negotiation has failed
+                _ => Response::build_from(
+                    response::content::Plain(self.reason().to_string()).respond_to(request)?,
+                )
                 .status(http_status)
-                .ok()
+                .ok(),
+            }
         }
     }
 }

src/routes/snippets.rs

@@ -11,7 +11,8 @@ use crate::application::Config;
 use crate::errors::ApiError;
 use crate::storage::{Changeset, DateTime, Direction, ListSnippetsQuery, Snippet, Storage};
 use crate::web::{
-    BearerAuth, Input, NegotiatedContentType, Output, PaginationLimit, WithHttpHeaders,
+    BearerAuth, DoNotAcceptAny, Input, NegotiatedContentType, Output, PaginationLimit,
+    WithHttpHeaders,
 };
 
 fn create_snippet_impl(
@@ -260,7 +261,27 @@ pub fn import_snippet(
     create_snippet_impl(&**storage, &snippet, base_path)
 }
 
-#[get("/snippets/<id>")]
+#[get("/snippets/<id>", format = "text/plain", rank = 1)]
+pub fn get_raw_snippet(
+    storage: State<Box<dyn Storage>>,
+    id: String,
+    _user: BearerAuth,
+    // W/o this, a request specifying any media type (i.e. */*), would be matched by this route,
+    // which is not what we want. We can't add the desired format to the route below, because it's
+    // supposed to perform content negotiation and return an ApiError when a user requests an
+    // unsupported format.
+    _not_any: DoNotAcceptAny,
+) -> Result<String, ApiError> {
+    Ok(storage
+        .get(&id)?
+        .changesets
+        .into_iter()
+        .last()
+        .map(|c| c.content)
+        .unwrap_or_default())
+}
+
+#[get("/snippets/<id>", rank = 2)]
 pub fn get_snippet(
     storage: State<Box<dyn Storage>>,
     id: String,

src/web.rs

@@ -4,6 +4,6 @@ mod tracing;
 
 pub use crate::web::auth::{AuthValidator, BearerAuth, JwtValidator, User};
 pub use crate::web::content::{
-    Input, NegotiatedContentType, Output, PaginationLimit, WithHttpHeaders,
+    DoNotAcceptAny, Input, NegotiatedContentType, Output, PaginationLimit, WithHttpHeaders,
 };
 pub use crate::web::tracing::{RequestId, RequestIdHeader, RequestSpan};

src/web/content.rs

@@ -232,3 +232,20 @@ impl<'a, 'r> FromRequest<'a, 'r> for NegotiatedContentType {
         }
     }
 }
+
+/// A request guard that only accepts request that specify a specific media type
+/// via the Accept header.
+pub struct DoNotAcceptAny;
+
+impl<'a, 'r> FromRequest<'a, 'r> for DoNotAcceptAny {
+    type Error = ApiError;
+
+    fn from_request(request: &'a Request<'r>) -> request::Outcome<Self, Self::Error> {
+        match request.accept() {
+            // Accept is passed and it's not */*
+            Some(accept) if !accept.preferred().is_any() => Success(DoNotAcceptAny),
+            // Accept is not passed, or it's not specific (i.e. */*)
+            _ => Forward(()),
+        }
+    }
+}

tests/gabbits/get-snippet-errors.yaml

@@ -35,3 +35,15 @@ tests:
     status: 404
     response_headers:
       x-request-id: *request_id_regex
+
+  - name: retrieve the raw content of a snippet (not found)
+    GET: /v1/snippets/foobar
+    request_headers:
+      accept: text/plain
+    response_headers:
+      content-type: text/plain; charset=utf-8
+    response_strings:
+      - Snippet with id `foobar` is not found
+    status: 404
+    response_headers:
+      x-request-id: *request_id_regex

tests/gabbits/get-snippet.yaml

@@ -80,6 +80,17 @@ tests:
       $.`len`: 7
     status: 200
 
+  - name: retrieve the raw content of a snippet
+    GET: /v1/snippets/$HISTORY['create a new snippet'].$RESPONSE['id']
+    request_headers:
+      accept: "text/plain"
+    response_headers:
+      content-type: text/plain; charset=utf-8
+      x-request-id: *request_id_regex
+    response_strings:
+      - print('Hello, World!')
+    status: 200
+
   - name: retrieve previously created snippet by ID (multiple accept types)
     GET: /v1/snippets/$HISTORY['create a new snippet'].$RESPONSE['id']
     request_headers: