rskit-httpclient 0.2.0-alpha.3

//! HTTP client implementation.

use crate::config::HttpClientConfig;
use crate::request::{Request, RequestBody};
use crate::response::Response;
use crate::tls::apply_tls;
use crate::transport::{
    map_transport_error, parse_header_name, parse_header_value, read_response_body, redirect_policy,
};

use reqwest::Client;
use rskit_errors::{AppError, AppResult, ErrorCode};
use serde::Serialize;
use serde::de::DeserializeOwned;

/// Async HTTP client with auth, headers, and error handling.
///
/// # Security
/// TLS certificate verification must never be disabled in production.
/// `danger_accept_invalid_certs` is only available behind the `danger-tls` feature flag
/// and must not be enabled in release builds.
#[derive(Clone)]
pub struct HttpClient {
    client: Client,
    config: HttpClientConfig,
}

impl HttpClient {
    /// Creates a new HTTP client with the given configuration.
    pub fn new(config: HttpClientConfig) -> AppResult<Self> {
        let mut builder = Client::builder()
            .timeout(config.timeout)
            .connect_timeout(config.connect_timeout)
            .redirect(redirect_policy(&config));

        if let Some(ua) = &config.user_agent {
            builder = builder.user_agent(ua.clone());
        }
        if let Some(tls) = &config.tls {
            builder = apply_tls(builder, tls)?;
        }

        let client = builder.build().map_err(|e| {
            AppError::new(
                ErrorCode::Internal,
                format!("failed to build http client: {e}"),
            )
            .with_cause(e)
        })?;

        Ok(Self { client, config })
    }

    /// Wraps an existing reqwest client with canonical configuration metadata.
    #[must_use]
    pub fn from_parts(config: HttpClientConfig, client: Client) -> Self {
        Self { client, config }
    }

    /// Gets the configuration.
    pub fn config(&self) -> &HttpClientConfig {
        &self.config
    }

    /// Executes an HTTP request.
    pub async fn send(&self, req: Request) -> AppResult<Response> {
        let mut response = self.execute_with_resilience(req).await?;

        let status = response.status();
        let headers = response
            .headers()
            .iter()
            .map(|(k, v)| {
                (
                    k.to_string(),
                    v.to_str().unwrap_or("<non-utf8>").to_string(),
                )
            })
            .collect();

        let body = read_response_body(&mut response, self.config.max_response_body_bytes).await?;

        Ok(Response::new(status, headers, body))
    }

    async fn execute_with_resilience(&self, req: Request) -> AppResult<reqwest::Response> {
        if let Some(policy) = &self.config.resilience_policy {
            policy
                .execute(|| async { self.execute_transport(req.clone()).await })
                .await
        } else {
            self.execute_transport(req).await
        }
    }

    async fn execute_transport(&self, req: Request) -> AppResult<reqwest::Response> {
        self.build_request(&req)?
            .send()
            .await
            .map_err(map_transport_error)
    }

    fn build_request(&self, req: &Request) -> AppResult<reqwest::RequestBuilder> {
        let url = self.build_url(&req.path)?;
        self.config.destination_policy.validate(&url)?;
        let mut request = match req.method.as_str() {
            "GET" => self.client.get(url),
            "POST" => self.client.post(url),
            "PUT" => self.client.put(url),
            "PATCH" => self.client.patch(url),
            "DELETE" => self.client.delete(url),
            "HEAD" => self.client.head(url),
            method => {
                return Err(AppError::new(
                    ErrorCode::InvalidInput,
                    format!("unsupported http method: {}", method),
                ));
            }
        };

        for (name, value) in &self.config.default_headers {
            let hn = parse_header_name(name)?;
            let hv = parse_header_value(name, value)?;
            request = request.header(hn, hv);
        }

        for (name, value) in &req.headers {
            let hn = parse_header_name(name)?;
            let hv = parse_header_value(name, value)?;
            request = request.header(hn, hv);
        }

        if let Some(query) = &req.query {
            request = request.query(query);
        }

        let auth = req.auth.as_ref().or(self.config.auth.as_ref());
        if let Some(auth) = auth
            && let Some((name, value)) = auth.header()?
        {
            let hn = parse_header_name(&name)?;
            let hv = parse_header_value(&name, &value)?;
            request = request.header(hn, hv);
        }

        if let Some(body) = &req.body {
            request = match body {
                RequestBody::Json(value) => request.json(value),
                RequestBody::Text(text) => request.body(text.clone()),
                RequestBody::Bytes(bytes) => request.body(bytes.clone()),
            };
        }

        Ok(request)
    }

    /// Executes a GET request and returns the response.
    pub async fn get(&self, path: &str) -> AppResult<Response> {
        self.send(Request::get(path)).await
    }

    /// Executes a request and converts non-2xx responses into an error.
    pub async fn send_checked(&self, req: Request) -> AppResult<Response> {
        self.send(req).await?.error_for_status()
    }

    /// Executes a GET request and parses the response as JSON.
    pub async fn get_json<T: DeserializeOwned>(&self, path: &str) -> AppResult<T> {
        self.get(path).await?.checked_json()
    }

    /// Executes a POST request with a JSON body.
    pub async fn post<T: Serialize>(&self, path: &str, body: &T) -> AppResult<Response> {
        let req = Request::post(path).json_body(body)?;
        self.send(req).await
    }

    /// Executes a POST request with a JSON body and parses the response as JSON.
    pub async fn post_json<T: Serialize, R: DeserializeOwned>(
        &self,
        path: &str,
        body: &T,
    ) -> AppResult<R> {
        self.post(path, body).await?.checked_json()
    }

    /// Executes a PUT request with a JSON body.
    pub async fn put<T: Serialize>(&self, path: &str, body: &T) -> AppResult<Response> {
        let req = Request::put(path).json_body(body)?;
        self.send(req).await
    }

    /// Executes a PUT request with a JSON body and parses the response as JSON.
    pub async fn put_json<T: Serialize, R: DeserializeOwned>(
        &self,
        path: &str,
        body: &T,
    ) -> AppResult<R> {
        self.put(path, body).await?.checked_json()
    }

    /// Executes a PATCH request with a JSON body.
    pub async fn patch<T: Serialize>(&self, path: &str, body: &T) -> AppResult<Response> {
        let req = Request::patch(path).json_body(body)?;
        self.send(req).await
    }

    /// Executes a PATCH request with a JSON body and parses the response as JSON.
    pub async fn patch_json<T: Serialize, R: DeserializeOwned>(
        &self,
        path: &str,
        body: &T,
    ) -> AppResult<R> {
        self.patch(path, body).await?.checked_json()
    }

    /// Executes a DELETE request.
    pub async fn delete(&self, path: &str) -> AppResult<Response> {
        self.send(Request::delete(path)).await
    }

    /// Executes a HEAD request.
    pub async fn head(&self, path: &str) -> AppResult<Response> {
        self.send(Request::head(path)).await
    }

    /// Builds the full URL from a path.
    fn build_url(&self, path: &str) -> AppResult<reqwest::Url> {
        if let Some(base) = &self.config.base_url {
            // Handle path to ensure correct joining
            let base_ends_slash = base.ends_with('/');
            let path_starts_slash = path.starts_with('/');

            let url = match (base_ends_slash, path_starts_slash) {
                (true, true) => format!("{}{}", base.trim_end_matches('/'), path),
                (true, false) | (false, true) => format!("{}{}", base, path),
                (false, false) => format!("{}/{}", base, path),
            };

            url.parse::<reqwest::Url>().map_err(|e| {
                AppError::new(ErrorCode::InvalidInput, format!("invalid url: {e}")).with_cause(e)
            })
        } else {
            path.parse::<reqwest::Url>().map_err(|e| {
                AppError::new(ErrorCode::InvalidInput, format!("invalid url: {e}")).with_cause(e)
            })
        }
    }
}

impl std::fmt::Debug for HttpClient {
    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
        f.debug_struct("HttpClient")
            .field("config", &self.config)
            .finish()
    }
}

#[cfg(test)]
mod tests {
    use super::*;

    #[test]
    fn test_url_building() {
        let config = HttpClientConfig::new().with_base_url("https://api.example.com/v1");
        let client = HttpClient::new(config).unwrap();

        let url = client.build_url("/users").unwrap();
        assert_eq!(url.as_str(), "https://api.example.com/v1/users");

        let url = client.build_url("users").unwrap();
        assert_eq!(url.as_str(), "https://api.example.com/v1/users");
    }

    #[test]
    fn test_url_building_without_base() {
        let config = HttpClientConfig::new();
        let client = HttpClient::new(config).unwrap();

        let url = client.build_url("https://example.com/users").unwrap();
        assert_eq!(url.as_str(), "https://example.com/users");
    }

    #[test]
    fn test_client_creation() {
        let config = HttpClientConfig::new()
            .with_base_url("https://api.example.com")
            .with_user_agent("test-client/1.0");

        let client = HttpClient::new(config).unwrap();
        assert!(client.config.base_url.is_some());
        assert_eq!(
            client.config.user_agent,
            Some("test-client/1.0".to_string())
        );
    }

    #[test]
    fn from_parts_preserves_config_and_debug_uses_redacted_config() {
        let config = HttpClientConfig::new()
            .with_base_url("https://api.example.com")
            .with_auth(crate::Auth::bearer("secret-token"));
        let client = HttpClient::from_parts(config, reqwest::Client::new());

        assert_eq!(
            client.config().base_url.as_deref(),
            Some("https://api.example.com")
        );
        let debug = format!("{client:?}");
        assert!(debug.contains("HttpClient"));
        assert!(debug.contains("SecretString(***)"));
        assert!(!debug.contains("secret-token"));
    }

    #[test]
    fn base_url_joining_handles_all_slash_combinations() {
        let cases = [
            (
                "https://api.example.com/v1/",
                "/users",
                "https://api.example.com/v1/users",
            ),
            (
                "https://api.example.com/v1/",
                "users",
                "https://api.example.com/v1/users",
            ),
            (
                "https://api.example.com/v1",
                "/users",
                "https://api.example.com/v1/users",
            ),
            (
                "https://api.example.com/v1",
                "users",
                "https://api.example.com/v1/users",
            ),
        ];

        for (base, path, expected) in cases {
            let client = HttpClient::new(HttpClientConfig::new().with_base_url(base)).unwrap();

            assert_eq!(client.build_url(path).unwrap().as_str(), expected);
        }
    }

    #[test]
    fn destination_policy_rejects_initial_url() {
        let config = HttpClientConfig::new();
        let client = HttpClient::new(config).unwrap();

        let result = client.build_request(&Request::get("http://169.254.169.254/latest"));

        assert!(result.is_err());
    }
}