Merge #2678

2678: Accept either an array of documents or a single document r=irevoire a=Kerollmops

# Pull Request

## What does this PR do?
Fixes #2671

## PR checklist
Please check if your PR fulfills the following requirements:
- [x] Does this PR fix an existing issue?
- [x] Have you read the contributing guidelines?
- [x] Have you made sure that the title is accurate and descriptive of the changes?


Co-authored-by: Clément Renault <clement@meilisearch.com>

Cargo.lock

@@ -983,6 +983,9 @@ name = "either"
 version = "1.6.1"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "e78d4f1cc4ae33bbfc157ed5d5a5ef3bc29227303d595861deb238fcec4e9457"
+dependencies = [
+ "serde",
+]
 
 [[package]]
 name = "embedded-hal"

meilisearch-http/tests/documents/add_documents.rs

@@ -52,6 +52,51 @@ async fn add_documents_test_json_content_types() {
     assert_eq!(response["taskUid"], 1);
 }
 
+/// Here we try to send a single document instead of an array with a single document inside.
+#[actix_rt::test]
+async fn add_single_document_test_json_content_types() {
+    let document = json!({
+        "id": 1,
+        "content": "Bouvier Bernois",
+    });
+
+    // this is a what is expected and should work
+    let server = Server::new().await;
+    let app = test::init_service(create_app!(
+        &server.service.meilisearch,
+        &server.service.auth,
+        true,
+        &server.service.options,
+        analytics::MockAnalytics::new(&server.service.options).0
+    ))
+    .await;
+    // post
+    let req = test::TestRequest::post()
+        .uri("/indexes/dog/documents")
+        .set_payload(document.to_string())
+        .insert_header(("content-type", "application/json"))
+        .to_request();
+    let res = test::call_service(&app, req).await;
+    let status_code = res.status();
+    let body = test::read_body(res).await;
+    let response: Value = serde_json::from_slice(&body).unwrap_or_default();
+    assert_eq!(status_code, 202);
+    assert_eq!(response["taskUid"], 0);
+
+    // put
+    let req = test::TestRequest::put()
+        .uri("/indexes/dog/documents")
+        .set_payload(document.to_string())
+        .insert_header(("content-type", "application/json"))
+        .to_request();
+    let res = test::call_service(&app, req).await;
+    let status_code = res.status();
+    let body = test::read_body(res).await;
+    let response: Value = serde_json::from_slice(&body).unwrap_or_default();
+    assert_eq!(status_code, 202);
+    assert_eq!(response["taskUid"], 1);
+}
+
 /// any other content-type is must be refused
 #[actix_rt::test]
 async fn error_add_documents_test_bad_content_types() {
@@ -327,7 +372,7 @@ async fn error_add_malformed_json_documents() {
     assert_eq!(
         response["message"],
         json!(
-            r#"The `json` payload provided is malformed. `Couldn't serialize document value: invalid type: string "0123456789012345678901234567...890123456789012345678901234567890123456789", expected a sequence at line 1 column 102`."#
+            r#"The `json` payload provided is malformed. `Couldn't serialize document value: data did not match any variant of untagged enum Either`."#
         )
     );
     assert_eq!(response["code"], json!("malformed_payload"));
@@ -350,7 +395,7 @@ async fn error_add_malformed_json_documents() {
     assert_eq!(status_code, 400);
     assert_eq!(
         response["message"],
-        json!("The `json` payload provided is malformed. `Couldn't serialize document value: invalid type: string \"0123456789012345678901234567...90123456789012345678901234567890123456789m\", expected a sequence at line 1 column 103`.")
+        json!("The `json` payload provided is malformed. `Couldn't serialize document value: data did not match any variant of untagged enum Either`.")
     );
     assert_eq!(response["code"], json!("malformed_payload"));
     assert_eq!(response["type"], json!("invalid_request"));

meilisearch-lib/Cargo.toml

@@ -15,7 +15,7 @@ clap = { version = "3.1.6", features = ["derive", "env"] }
 crossbeam-channel = "0.5.2"
 csv = "1.1.6"
 derivative = "2.2.0"
-either = "1.6.1"
+either = { version = "1.6.1", features = ["serde"] }
 flate2 = "1.0.22"
 fs_extra = "1.2.0"
 fst = "0.4.7"

meilisearch-lib/src/document_formats.rs

@@ -2,9 +2,12 @@ use std::borrow::Borrow;
 use std::fmt::{self, Debug, Display};
 use std::io::{self, BufReader, Read, Seek, Write};
 
+use either::Either;
 use meilisearch_types::error::{Code, ErrorCode};
 use meilisearch_types::internal_error;
 use milli::documents::{DocumentsBatchBuilder, Error};
+use milli::Object;
+use serde::Deserialize;
 
 type Result<T> = std::result::Result<T, DocumentFormatError>;
 
@@ -124,11 +127,18 @@ pub fn read_json(input: impl Read, writer: impl Write + Seek) -> Result<usize> {
     let mut builder = DocumentsBatchBuilder::new(writer);
     let reader = BufReader::new(input);
 
-    let objects: Vec<_> = serde_json::from_reader(reader)
+    #[derive(Deserialize, Debug)]
+    #[serde(transparent)]
+    struct ArrayOrSingleObject {
+        #[serde(with = "either::serde_untagged")]
+        inner: Either<Vec<Object>, Object>,
+    }
+
+    let content: ArrayOrSingleObject = serde_json::from_reader(reader)
         .map_err(Error::Json)
         .map_err(|e| (PayloadType::Json, e))?;
 
-    for object in objects {
+    for object in content.inner.map_right(|o| vec![o]).into_inner() {
         builder
             .append_json_object(&object)
             .map_err(Into::into)