server: return HTTP 400 for invalid embedding requests (#29060)

tools/server/server-common.cpp

@@ -1008,7 +1008,7 @@ server_tokens tokenize_input_subprompt(const llama_vocab * vocab, mtmd_context *
             return server_tokens(tmp, false);
         }
    } else {
-       throw std::runtime_error("\"prompt\" elements must be a string, a list of tokens, a JSON object containing a prompt string, or a list of mixed strings & tokens.");
+       throw std::invalid_argument("\"prompt\" elements must be a string, a list of tokens, a JSON object containing a prompt string, or a list of mixed strings & tokens.");
    }
 }
 
@@ -1023,7 +1023,7 @@ std::vector<server_tokens> tokenize_input_prompts(const llama_vocab * vocab, mtm
         result.push_back(tokenize_input_subprompt(vocab, mctx, json_prompt, add_special, parse_special, init_opt));
     }
     if (result.empty()) {
-        throw std::runtime_error("\"prompt\" must not be empty");
+        throw std::invalid_argument("\"prompt\" must not be empty");
     }
     return result;
 }

tools/server/server.cpp

@@ -61,6 +61,10 @@ static server_http_context::handler_t ex_wrapper(server_http_context::handler_t
             // treat invalid_argument as invalid request (400)
             error = ERROR_TYPE_INVALID_REQUEST;
             message = e.what();
+        } catch (const common_json_error & e) {
+            // JSON parse and type errors are invalid requests (400)
+            error = ERROR_TYPE_INVALID_REQUEST;
+            message = e.what();
         } catch (const std::exception & e) {
             // treat other exceptions as server error (500)
             error = ERROR_TYPE_SERVER;

tools/server/tests/unit/test_embedding.py

@@ -327,3 +327,21 @@ def test_embedding_openai_library_base64():
     # make sure the decoded data is the same as the original
     for x, y in zip(floats, vec0):
         assert abs(x - y) < EPSILON
+
+
+@pytest.mark.parametrize(
+    "data",
+    [
+        {"input": []},
+        {"input": True},
+        {"input": "hello", "encoding_format": 1},
+    ]
+)
+def test_embedding_invalid_request(data):
+    global server
+    server.pooling = 'last'
+    server.start()
+    res = server.make_request("POST", "/v1/embeddings", data=data)
+    assert res.status_code == 400
+    assert "error" in res.body
+    assert res.body["error"]["type"] == "invalid_request_error"