Allow up to 5 extractors (#1382)

Author: JuliDi

CHANGELOG.adoc

@@ -15,6 +15,8 @@
 
 https://github.com/oxidecomputer/dropshot/compare/v0.16.2\...HEAD[Full list of commits]
 
+* https://github.com/oxidecomputer/dropshot/pull/1382[#1382] Allow 2 more `SharedExtractor`s to be used with the `endpoint` macro
+
 == 0.16.2 (released 2025-05-21)
 
 https://github.com/oxidecomputer/dropshot/compare/v0.16.1\...v0.16.2[Full list of commits]

dropshot/src/extractor/common.rs

@@ -203,7 +203,9 @@ macro_rules! impl_rqextractor_for_tuple {
     }
 }}
 
-// Implement `RequestExtractor` for any tuple consisting of 0-2 shared
+// Implement `RequestExtractor` for any tuple consisting of 0-4 shared
 // extractors and exactly one exclusive extractor.
 impl_rqextractor_for_tuple!(S1);
 impl_rqextractor_for_tuple!(S1, S2);
+impl_rqextractor_for_tuple!(S1, S2, S3);
+impl_rqextractor_for_tuple!(S1, S2, S3, S4);

dropshot/src/handler.rs

@@ -680,6 +680,14 @@ impl_HttpHandlerFunc_for_func_with_params!();
 impl_HttpHandlerFunc_for_func_with_params!((0, T0));
 impl_HttpHandlerFunc_for_func_with_params!((0, T1), (1, T2));
 impl_HttpHandlerFunc_for_func_with_params!((0, T1), (1, T2), (2, T3));
+impl_HttpHandlerFunc_for_func_with_params!((0, T1), (1, T2), (2, T3), (3, T4));
+impl_HttpHandlerFunc_for_func_with_params!(
+    (0, T1),
+    (1, T2),
+    (2, T3),
+    (3, T4),
+    (4, T5)
+);
 
 /// `RouteHandler` abstracts an `HttpHandlerFunc<FuncParams, ResponseType>` in a
 /// way that allows callers to invoke the handler without knowing the handler's

dropshot/src/lib.rs

@@ -342,7 +342,7 @@
 //!
 //! `Query` and `Path` impl `SharedExtractor`.  `TypedBody`, `UntypedBody`,
 //! `StreamingBody`, and `RawRequest` impl `ExclusiveExtractor`.  Your function
-//! may accept 0-3 extractors, but only one can be `ExclusiveExtractor`, and it
+//! may accept 0-5 extractors, but only one can be `ExclusiveExtractor`, and it
 //! must be the last one.  Otherwise, the order of extractor arguments does not
 //! matter.
 //!

dropshot/tests/integration-tests/openapi.rs

@@ -616,6 +616,78 @@ async fn handler30(
     todo!();
 }
 
+#[derive(Deserialize, JsonSchema)]
+struct PathArgs31 {
+    #[expect(unused)]
+    aa: String,
+}
+
+#[derive(Deserialize, JsonSchema)]
+struct Headers31 {
+    #[expect(unused)]
+    header_a: String,
+}
+
+#[derive(Deserialize, JsonSchema)]
+struct Query31 {
+    #[expect(unused)]
+    query_a: String,
+}
+
+#[endpoint {
+    method = GET,
+    path = "/testing/{aa}",
+    tags = ["it"]
+}]
+async fn handler31(
+    _: RequestContext<()>,
+    _: Path<PathArgs31>,
+    _: Header<Headers31>,
+    _: Query<Query31>,
+    _: UntypedBody,
+) -> Result<HttpResponseOk<CoolStruct>, HttpError> {
+    todo!();
+}
+
+#[derive(Debug, Clone, Serialize, JsonSchema)]
+pub struct CustomShared32 {
+    pub a: String,
+}
+
+#[async_trait::async_trait]
+impl dropshot::SharedExtractor for CustomShared32 {
+    async fn from_request<Context: dropshot::ServerContext>(
+        _rqctx: &RequestContext<Context>,
+    ) -> Result<Self, HttpError> {
+        Ok(Self { a: "test".to_string() })
+    }
+
+    fn metadata(
+        _body_content_type: dropshot::ApiEndpointBodyContentType,
+    ) -> dropshot::ExtractorMetadata {
+        dropshot::ExtractorMetadata {
+            extension_mode: dropshot::ExtensionMode::None,
+            parameters: vec![],
+        }
+    }
+}
+
+#[endpoint {
+    method = GET,
+    path = "/testing32/{aa}",
+    tags = ["it"]
+}]
+async fn handler32(
+    _: RequestContext<()>,
+    _: Path<PathArgs31>,
+    _: Header<Headers31>,
+    _: Query<Query31>,
+    _: CustomShared32,
+    _: UntypedBody,
+) -> Result<HttpResponseOk<CoolStruct>, HttpError> {
+    todo!();
+}
+
 fn make_api(
     maybe_tag_config: Option<TagConfig>,
 ) -> Result<ApiDescription<()>, ApiDescriptionRegisterError> {
@@ -655,6 +727,8 @@ fn make_api(
     api.register(handler28)?;
     api.register(handler29)?;
     api.register(handler30)?;
+    api.register(handler31)?;
+    api.register(handler32)?;
     Ok(api)
 }
 

dropshot/tests/test_openapi.json

@@ -764,6 +764,69 @@
         }
       }
     },
+    "/testing/{aa}": {
+      "get": {
+        "tags": [
+          "it"
+        ],
+        "operationId": "handler31",
+        "parameters": [
+          {
+            "in": "path",
+            "name": "aa",
+            "required": true,
+            "schema": {
+              "type": "string"
+            }
+          },
+          {
+            "in": "header",
+            "name": "header_a",
+            "required": true,
+            "schema": {
+              "type": "string"
+            }
+          },
+          {
+            "in": "query",
+            "name": "query_a",
+            "required": true,
+            "schema": {
+              "type": "string"
+            }
+          }
+        ],
+        "requestBody": {
+          "content": {
+            "application/octet-stream": {
+              "schema": {
+                "type": "string",
+                "format": "binary"
+              }
+            }
+          },
+          "required": true
+        },
+        "responses": {
+          "200": {
+            "description": "successful operation",
+            "content": {
+              "application/json": {
+                "schema": {
+                  "$ref": "#/components/schemas/CoolStruct"
+                }
+              }
+            }
+          },
+          "4XX": {
+            "$ref": "#/components/responses/Error"
+          },
+          "5XX": {
+            "$ref": "#/components/responses/Error"
+          }
+        }
+      }
+    },
     "/testing/{aa}/{bb}": {
       "put": {
         "tags": [
@@ -808,6 +871,69 @@
         }
       }
     },
+    "/testing32/{aa}": {
+      "get": {
+        "tags": [
+          "it"
+        ],
+        "operationId": "handler32",
+        "parameters": [
+          {
+            "in": "path",
+            "name": "aa",
+            "required": true,
+            "schema": {
+              "type": "string"
+            }
+          },
+          {
+            "in": "header",
+            "name": "header_a",
+            "required": true,
+            "schema": {
+              "type": "string"
+            }
+          },
+          {
+            "in": "query",
+            "name": "query_a",
+            "required": true,
+            "schema": {
+              "type": "string"
+            }
+          }
+        ],
+        "requestBody": {
+          "content": {
+            "application/octet-stream": {
+              "schema": {
+                "type": "string",
+                "format": "binary"
+              }
+            }
+          },
+          "required": true
+        },
+        "responses": {
+          "200": {
+            "description": "successful operation",
+            "content": {
+              "application/json": {
+                "schema": {
+                  "$ref": "#/components/schemas/CoolStruct"
+                }
+              }
+            }
+          },
+          "4XX": {
+            "$ref": "#/components/responses/Error"
+          },
+          "5XX": {
+            "$ref": "#/components/responses/Error"
+          }
+        }
+      }
+    },
     "/thing_with_headers": {
       "get": {
         "tags": [