allow request mutation and async code in prehooks (#457)

example-macro/src/main.rs

@@ -8,10 +8,27 @@ generate_api!(
     pre_hook = (|_, request| {
         println!("doing this {:?}", request);
     }),
+    pre_hook_async = crate::add_auth_headers,
     post_hook = crate::all_done,
     derives = [schemars::JsonSchema],
 );
 
+async fn add_auth_headers(
+    _: &(),
+    req: &mut reqwest::Request,
+) -> Result<(), reqwest::header::InvalidHeaderValue> {
+    // You can perform asynchronous, fallible work in a request hook, then
+    // modify the request right before it is transmitted to the server; e.g.,
+    // for generating an authenticaiton signature based on the complete set of
+    // request header values:
+    req.headers_mut().insert(
+        reqwest::header::AUTHORIZATION,
+        reqwest::header::HeaderValue::from_str("legitimate")?,
+    );
+
+    Ok(())
+}
+
 fn all_done(_: &(), _result: &reqwest::Result<reqwest::Response>) {}
 
 mod buildomat {

progenitor-client/src/progenitor_client.rs

@@ -249,13 +249,17 @@ pub enum Error<E = ()> {
     /// A response not listed in the API description. This may represent a
     /// success or failure response; check `status().is_success()`.
     UnexpectedResponse(reqwest::Response),
+
+    /// An error occurred in the processing of a request pre-hook.
+    PreHookError(String),
 }
 
 impl<E> Error<E> {
     /// Returns the status code, if the error was generated from a response.
     pub fn status(&self) -> Option<reqwest::StatusCode> {
         match self {
             Error::InvalidRequest(_) => None,
+            Error::PreHookError(_) => None,
             Error::CommunicationError(e) => e.status(),
             Error::ErrorResponse(rv) => Some(rv.status()),
             Error::InvalidUpgrade(e) => e.status(),
@@ -272,6 +276,7 @@ impl<E> Error<E> {
     pub fn into_untyped(self) -> Error {
         match self {
             Error::InvalidRequest(s) => Error::InvalidRequest(s),
+            Error::PreHookError(s) => Error::PreHookError(s),
             Error::CommunicationError(e) => Error::CommunicationError(e),
             Error::ErrorResponse(ResponseValue {
                 inner: _,
@@ -332,6 +337,9 @@ where
             Error::UnexpectedResponse(r) => {
                 write!(f, "Unexpected Response: {:?}", r)
             }
+            Error::PreHookError(s) => {
+                write!(f, "Pre-hook Error: {}", s)
+            }
         }
     }
 }

progenitor-impl/src/lib.rs

@@ -60,6 +60,7 @@ pub struct GenerationSettings {
     tag: TagStyle,
     inner_type: Option<TokenStream>,
     pre_hook: Option<TokenStream>,
+    pre_hook_async: Option<TokenStream>,
     post_hook: Option<TokenStream>,
     extra_derives: Vec<String>,
 
@@ -128,6 +129,12 @@ impl GenerationSettings {
         self
     }
 
+    /// Hook invoked before issuing the HTTP request.
+    pub fn with_pre_hook_async(&mut self, pre_hook: TokenStream) -> &mut Self {
+        self.pre_hook_async = Some(pre_hook);
+        self
+    }
+
     /// Hook invoked prior to receiving the HTTP response.
     pub fn with_post_hook(&mut self, post_hook: TokenStream) -> &mut Self {
         self.post_hook = Some(post_hook);

progenitor-impl/src/method.rs

@@ -1141,6 +1141,14 @@ impl Generator {
                 (#hook)(&#client.inner, &#request_ident);
             }
         });
+        let pre_hook_async = self.settings.pre_hook_async.as_ref().map(|hook| {
+            quote! {
+                match (#hook)(&#client.inner, &mut #request_ident).await {
+                    Ok(_) => (),
+                    Err(e) => return Err(Error::PreHookError(e.to_string())),
+                }
+            }
+        });
         let post_hook = self.settings.post_hook.as_ref().map(|hook| {
             quote! {
                 (#hook)(&#client.inner, &#result_ident);
@@ -1155,7 +1163,8 @@ impl Generator {
 
             #headers_build
 
-            let #request_ident = #client.client
+            #[allow(unused_mut)]
+            let mut #request_ident = #client.client
                 . #method_func (#url_ident)
                 #accept_header
                 #(#body_func)*
@@ -1165,6 +1174,7 @@ impl Generator {
                 .build()?;
 
             #pre_hook
+            #pre_hook_async
             let #result_ident = #client.client
                 .execute(#request_ident)
                 .await;

progenitor-impl/tests/output/src/buildomat_builder.rs

@@ -2404,7 +2404,8 @@ pub mod builder {
         pub async fn send(self) -> Result<ResponseValue<()>, Error<()>> {
             let Self { client } = self;
             let url = format!("{}/v1/control/hold", client.baseurl,);
-            let request = client
+            #[allow(unused_mut)]
+            let mut request = client
                 .client
                 .post(url)
                 .header(
@@ -2438,7 +2439,8 @@ pub mod builder {
         pub async fn send(self) -> Result<ResponseValue<()>, Error<()>> {
             let Self { client } = self;
             let url = format!("{}/v1/control/resume", client.baseurl,);
-            let request = client.client.post(url).build()?;
+            #[allow(unused_mut)]
+            let mut request = client.client.post(url).build()?;
             let result = client.client.execute(request).await;
             let response = result?;
             match response.status().as_u16() {
@@ -2484,7 +2486,8 @@ pub mod builder {
                 client.baseurl,
                 encode_path(&task.to_string()),
             );
-            let request = client
+            #[allow(unused_mut)]
+            let mut request = client
                 .client
                 .get(url)
                 .header(
@@ -2518,7 +2521,8 @@ pub mod builder {
         pub async fn send(self) -> Result<ResponseValue<Vec<types::Task>>, Error<()>> {
             let Self { client } = self;
             let url = format!("{}/v1/tasks", client.baseurl,);
-            let request = client
+            #[allow(unused_mut)]
+            let mut request = client
                 .client
                 .get(url)
                 .header(
@@ -2579,7 +2583,8 @@ pub mod builder {
                 .and_then(|v| types::TaskSubmit::try_from(v).map_err(|e| e.to_string()))
                 .map_err(Error::InvalidRequest)?;
             let url = format!("{}/v1/tasks", client.baseurl,);
-            let request = client
+            #[allow(unused_mut)]
+            let mut request = client
                 .client
                 .post(url)
                 .header(
@@ -2655,7 +2660,8 @@ pub mod builder {
             if let Some(v) = &minseq {
                 query.push(("minseq", v.to_string()));
             }
-            let request = client
+            #[allow(unused_mut)]
+            let mut request = client
                 .client
                 .get(url)
                 .header(
@@ -2709,7 +2715,8 @@ pub mod builder {
                 client.baseurl,
                 encode_path(&task.to_string()),
             );
-            let request = client
+            #[allow(unused_mut)]
+            let mut request = client
                 .client
                 .get(url)
                 .header(
@@ -2780,7 +2787,8 @@ pub mod builder {
                 encode_path(&task.to_string()),
                 encode_path(&output.to_string()),
             );
-            let request = client.client.get(url).build()?;
+            #[allow(unused_mut)]
+            let mut request = client.client.get(url).build()?;
             let result = client.client.execute(request).await;
             let response = result?;
             match response.status().as_u16() {
@@ -2834,7 +2842,8 @@ pub mod builder {
                 .and_then(|v| types::UserCreate::try_from(v).map_err(|e| e.to_string()))
                 .map_err(Error::InvalidRequest)?;
             let url = format!("{}/v1/users", client.baseurl,);
-            let request = client
+            #[allow(unused_mut)]
+            let mut request = client
                 .client
                 .post(url)
                 .header(
@@ -2869,7 +2878,8 @@ pub mod builder {
         pub async fn send(self) -> Result<ResponseValue<types::WhoamiResult>, Error<()>> {
             let Self { client } = self;
             let url = format!("{}/v1/whoami", client.baseurl,);
-            let request = client
+            #[allow(unused_mut)]
+            let mut request = client
                 .client
                 .get(url)
                 .header(
@@ -2919,7 +2929,8 @@ pub mod builder {
             let Self { client, body } = self;
             let body = body.map_err(Error::InvalidRequest)?;
             let url = format!("{}/v1/whoami/name", client.baseurl,);
-            let request = client
+            #[allow(unused_mut)]
+            let mut request = client
                 .client
                 .put(url)
                 .header(
@@ -2981,7 +2992,8 @@ pub mod builder {
                 .and_then(|v| types::WorkerBootstrap::try_from(v).map_err(|e| e.to_string()))
                 .map_err(Error::InvalidRequest)?;
             let url = format!("{}/v1/worker/bootstrap", client.baseurl,);
-            let request = client
+            #[allow(unused_mut)]
+            let mut request = client
                 .client
                 .post(url)
                 .header(
@@ -3016,7 +3028,8 @@ pub mod builder {
         pub async fn send(self) -> Result<ResponseValue<types::WorkerPingResult>, Error<()>> {
             let Self { client } = self;
             let url = format!("{}/v1/worker/ping", client.baseurl,);
-            let request = client
+            #[allow(unused_mut)]
+            let mut request = client
                 .client
                 .get(url)
                 .header(
@@ -3096,7 +3109,8 @@ pub mod builder {
                 client.baseurl,
                 encode_path(&task.to_string()),
             );
-            let request = client.client.post(url).json(&body).build()?;
+            #[allow(unused_mut)]
+            let mut request = client.client.post(url).json(&body).build()?;
             let result = client.client.execute(request).await;
             let response = result?;
             match response.status().as_u16() {
@@ -3155,7 +3169,8 @@ pub mod builder {
                 client.baseurl,
                 encode_path(&task.to_string()),
             );
-            let request = client
+            #[allow(unused_mut)]
+            let mut request = client
                 .client
                 .post(url)
                 .header(
@@ -3240,7 +3255,8 @@ pub mod builder {
                 client.baseurl,
                 encode_path(&task.to_string()),
             );
-            let request = client.client.post(url).json(&body).build()?;
+            #[allow(unused_mut)]
+            let mut request = client.client.post(url).json(&body).build()?;
             let result = client.client.execute(request).await;
             let response = result?;
             match response.status().as_u16() {
@@ -3311,7 +3327,8 @@ pub mod builder {
                 client.baseurl,
                 encode_path(&task.to_string()),
             );
-            let request = client.client.post(url).json(&body).build()?;
+            #[allow(unused_mut)]
+            let mut request = client.client.post(url).json(&body).build()?;
             let result = client.client.execute(request).await;
             let response = result?;
             match response.status().as_u16() {
@@ -3338,7 +3355,8 @@ pub mod builder {
         pub async fn send(self) -> Result<ResponseValue<types::WorkersResult>, Error<()>> {
             let Self { client } = self;
             let url = format!("{}/v1/workers", client.baseurl,);
-            let request = client
+            #[allow(unused_mut)]
+            let mut request = client
                 .client
                 .get(url)
                 .header(
@@ -3372,7 +3390,8 @@ pub mod builder {
         pub async fn send(self) -> Result<ResponseValue<()>, Error<()>> {
             let Self { client } = self;
             let url = format!("{}/v1/workers/recycle", client.baseurl,);
-            let request = client.client.post(url).build()?;
+            #[allow(unused_mut)]
+            let mut request = client.client.post(url).build()?;
             let result = client.client.execute(request).await;
             let response = result?;
             match response.status().as_u16() {