Use the spec's consumes for alternate forms of application/json (#449)

Author: bmc-msft

services/autorust/codegen/src/codegen.rs

@@ -47,6 +47,16 @@ impl CodeGen {
     pub fn should_box_property(&self, prop_nm: &PropertyName) -> bool {
         self.config.box_properties.contains(prop_nm)
     }
+
+    pub fn get_request_content_type_json(&self) -> String {
+        let consumes = self.spec.consumes();
+        consumes
+            .into_iter()
+            .filter(|x| x.starts_with("application/json"))
+            .map(|x| x.to_string())
+            .nth(0)
+            .unwrap_or_else(|| "application/json".to_string())
+    }
 }
 
 #[derive(Debug, thiserror::Error)]

services/autorust/codegen/src/codegen_operations.rs

@@ -135,6 +135,10 @@ fn create_function(cg: &CodeGen, doc_file: &Path, operation: &WebOperation) -> R
         }
     }
 
+    let has_content_type_header = parameters
+        .iter()
+        .any(|p| p.name.to_snake_case() == "content_type" && p.in_ == ParameterType::Header);
+
     // params
     let mut has_body_parameter = false;
     for param in &parameters {
@@ -220,16 +224,25 @@ fn create_function(cg: &CodeGen, doc_file: &Path, operation: &WebOperation) -> R
             }
             ParameterType::Body => {
                 has_body_parameter = true;
+                let set_content_type = if !has_content_type_header {
+                    let json_content_type = cg.get_request_content_type_json();
+                    quote! {
+                        req_builder = req_builder.header("content-type", #json_content_type);
+                    }
+                } else {
+                    quote! {}
+                };
+
                 if required {
                     ts_request_builder.extend(quote! {
-                        req_builder = req_builder.header("content-type", "application/json");
+                        #set_content_type
                         let req_body = azure_core::to_json(#param_name_var).map_err(#fname::Error::SerializeError)?;
                     });
                 } else {
                     ts_request_builder.extend(quote! {
                         let req_body =
                             if let Some(#param_name_var) = #param_name_var {
-                                req_builder = req_builder.header("content-type", "application/json");
+                                #set_content_type
                                 azure_core::to_json(#param_name_var).map_err(#fname::Error::SerializeError)?
                             } else {
                                 bytes::Bytes::from_static(azure_core::EMPTY_BODY)

services/autorust/codegen/src/spec.rs

@@ -81,6 +81,19 @@ impl Spec {
         &self.docs
     }
 
+    pub fn consumes(&self) -> Vec<&String> {
+        let versions: Vec<_> = self
+            .docs()
+            .values()
+            .filter(|doc| !doc.paths().is_empty())
+            .map(|api| &api.consumes)
+            .collect();
+
+        let mut versions: Vec<_> = versions.into_iter().flatten().collect();
+        versions.sort_unstable();
+        versions
+    }
+
     /// Look for specs with operations and return the last one sorted alphabetically
     pub fn api_version(&self) -> Option<String> {
         let mut versions: Vec<&str> = self