Conreg Feign

This crate provides procedural macros for creating Feign-like declarative HTTP clients.

Feign Client Macro

Used to create declarative HTTP clients similar to Java Feign. By annotating a trait with this macro, implementation code for HTTP requests is automatically generated, enabling RESTful communication between microservices.

Parameters

• service_id: Required, the unique identifier of the service, used for service discovery and load balancing.
• base_path: Optional, the base path prefix that will be prepended to all request paths.
• url: Optional, directly specifies the base URL for requests; if set, service_id and base_path will be ignored.

Example:

#[feign_client(service_id = "user-service", base_path = "/api")]
trait UserService{
  #[get("/api/users/{id}")]
  async fn get_user(&self, id: i32) -> Result<String, FeignError>;

  // ... other methods
}

// Then, you can use the generated client like this:
let client = UserServiceImpl::default();
let user = client.get_user(1).await?;

Http Method Macros

Supported HTTP Method Annotations

• #[get]
• #[post]
• #[put]
• #[delete]
• #[patch]

Parameter Binding Methods

Path Parameters

Use {param_name} placeholders in the path. When a method parameter name matches the placeholder name, it is automatically bound.

Example:

#[get("/api/users/{id}")]
async fn ip(&self, id: i32) -> Result<String, FeignError>;

Query Parameters

Use query = "{param}" to specify query parameter templates.

Example:

#[get(path = "/api/users", query = "id={id}")]
async fn query(&self, id: i32) -> Result<String, FeignError>;

Form Parameters

Use form = "{param}" to specify form data, supporting application/x-www-form-urlencoded and multipart/form-data.

Example:

#[post(path = "/api/login", form = "{loginForm}")]
async fn login(&self, loginForm: reqwest::multipart::Form) -> Result<String, FeignError>;

Body Parameter

Use body = "{param}" to specify the raw string body.

Example:

#[post(path = "/api/post", body = "{data}")]
async fn post(&self, data: String) -> Result<String, FeignError>;

JSON Parameter

Use json = "{param}" to specify JSON data; it will be automatically serialized and Content-Type: application/json will be set.

Note: need serde_json

Example:

#[post(path = "/api/post", json = "{data}")]
async fn post(&self, data: serde_json::Value) -> Result<String, FeignError> {}

Header Parameter

Use headers("Key=Value", ...) or headers("Key={param}", ...) to specify request headers, supporting both static values and dynamic parameters.

Example:

#[get(path = "/api/users", headers("Authorization: Bearer {token}", "Accept: application/json"))]
async fn get_users(&self, token: String) -> Result<String, FeignError>