Develop first version (#1)

Create first version of the library

The code is mainly taken from

* https://gitea.communiquons.org/pierre/oidc-test-client
* https://gitea.communiquons.org/pierre/BasicOIDC

with little improvements.

Reviewed-on: #1

src/client.rs

@@ -0,0 +1,82 @@
+//! # Open ID client implementation
+
+use base64::engine::general_purpose::STANDARD as BASE64_STANDARD;
+use base64::Engine;
+use std::collections::HashMap;
+use std::error::Error;
+
+use crate::primitives::{OpenIDConfig, OpenIDTokenResponse, OpenIDUserInfo};
+
+impl OpenIDConfig {
+    /// Load OpenID configuration from a given .well-known/openid-configuration URL
+    pub async fn load_from_url(url: &str) -> Result<Self, Box<dyn Error>> {
+        Ok(reqwest::get(url).await?.json().await?)
+    }
+
+    /// Get the authorization URL where a user should be redirect to perform authentication
+    pub fn gen_authorization_url(
+        &self,
+        client_id: &str,
+        state: &str,
+        redirect_uri: &str,
+    ) -> String {
+        let client_id = urlencoding::encode(client_id);
+        let state = urlencoding::encode(state);
+        let redirect_uri = urlencoding::encode(redirect_uri);
+
+        format!("{}?response_type=code&scope=openid%20profile%20email&client_id={client_id}&state={state}&redirect_uri={redirect_uri}", self.authorization_endpoint)
+    }
+
+    /// Query the token endpoint
+    ///
+    /// This endpoint returns both the parsed and the raw response, to allow handling
+    /// of bonus fields
+    pub async fn request_token(
+        &self,
+        client_id: &str,
+        client_secret: &str,
+        code: &str,
+        redirect_uri: &str,
+    ) -> Result<(OpenIDTokenResponse, String), Box<dyn Error>> {
+        let authorization = BASE64_STANDARD.encode(format!("{}:{}", client_id, client_secret));
+
+        let mut params = HashMap::new();
+        params.insert("grant_type", "authorization_code");
+        params.insert("code", code);
+        params.insert("redirect_uri", redirect_uri);
+
+        let response = reqwest::Client::new()
+            .post(&self.token_endpoint)
+            .header("Authorization", format!("Basic {authorization}"))
+            .form(&params)
+            .send()
+            .await?
+            .text()
+            .await?;
+
+        Ok((serde_json::from_str(&response)?, response))
+    }
+
+    /// Query the UserInfo endpoint.
+    ///
+    /// This endpoint should be use after having successfully retrieved the token
+    ///
+    /// This endpoint returns both the parsed value and the raw response, in case of presence
+    /// of additional fields
+    pub async fn request_user_info(
+        &self,
+        token: &OpenIDTokenResponse,
+    ) -> Result<(OpenIDUserInfo, String), Box<dyn Error>> {
+        let response = reqwest::Client::new()
+            .get(self.userinfo_endpoint.as_ref().expect(
+                "This client only support information retrieval through userinfo endpoint!",
+            ))
+            .header("Authorization", format!("Bearer {}", token.access_token))
+            .send()
+            .await?
+            .text()
+            .await?;
+
+        Ok((serde_json::from_str(&response)?, response))
+    }
+}