web_backend: Make Client use the PImpl idiom

Like with TelemetryJson, we can make the implementation details private
and avoid the need to expose httplib to external libraries that need to
use the Client class.

1 files changed, 141 insertions, 94 deletions

diff --git a/src/web_service/web_backend.cpp b/src/web_service/web_backend.cpp
index 787b0fbcb..b7737b615 100644
--- a/src/web_service/web_backend.cpp
+++ b/src/web_service/web_backend.cpp
@@ -3,9 +3,11 @@
 // Refer to the license.txt file included.
 
 #include <cstdlib>
+#include <mutex>
 #include <string>
-#include <thread>
 #include <LUrlParser.h>
+#include <httplib.h>
+#include "common/common_types.h"
 #include "common/logging/log.h"
 #include "common/web_result.h"
 #include "core/settings.h"
@@ -20,99 +22,132 @@ constexpr u32 HTTPS_PORT = 443;
 
 constexpr u32 TIMEOUT_SECONDS = 30;
 
-Client::JWTCache Client::jwt_cache{};
+struct Client::Impl {
+    Impl(std::string host, std::string username, std::string token)
+        : host{std::move(host)}, username{std::move(username)}, token{std::move(token)} {
+        std::lock_guard<std::mutex> lock(jwt_cache.mutex);
+        if (this->username == jwt_cache.username && this->token == jwt_cache.token) {
+            jwt = jwt_cache.jwt;
+        }
+    }
+
+    /// A generic function handles POST, GET and DELETE request together
+    Common::WebResult GenericJson(const std::string& method, const std::string& path,
+                                  const std::string& data, bool allow_anonymous) {
+        if (jwt.empty()) {
+            UpdateJWT();
+        }
+
+        if (jwt.empty() && !allow_anonymous) {
+            LOG_ERROR(WebService, "Credentials must be provided for authenticated requests");
+            return Common::WebResult{Common::WebResult::Code::CredentialsMissing,
+                                     "Credentials needed"};
+        }
+
+        auto result = GenericJson(method, path, data, jwt);
+        if (result.result_string == "401") {
+            // Try again with new JWT
+            UpdateJWT();
+            result = GenericJson(method, path, data, jwt);
+        }
 
-Client::Client(const std::string& host, const std::string& username, const std::string& token)
-    : host(host), username(username), token(token) {
-    std::lock_guard<std::mutex> lock(jwt_cache.mutex);
-    if (username == jwt_cache.username && token == jwt_cache.token) {
-        jwt = jwt_cache.jwt;
+        return result;
     }
-}
 
-Common::WebResult Client::GenericJson(const std::string& method, const std::string& path,
-                                      const std::string& data, const std::string& jwt,
-                                      const std::string& username, const std::string& token) {
-    if (cli == nullptr) {
-        auto parsedUrl = LUrlParser::clParseURL::ParseURL(host);
-        int port;
-        if (parsedUrl.m_Scheme == "http") {
-            if (!parsedUrl.GetPort(&port)) {
-                port = HTTP_PORT;
-            }
-            cli =
-                std::make_unique<httplib::Client>(parsedUrl.m_Host.c_str(), port, TIMEOUT_SECONDS);
-        } else if (parsedUrl.m_Scheme == "https") {
-            if (!parsedUrl.GetPort(&port)) {
-                port = HTTPS_PORT;
+    /**
+     * A generic function with explicit authentication method specified
+     * JWT is used if the jwt parameter is not empty
+     * username + token is used if jwt is empty but username and token are not empty
+     * anonymous if all of jwt, username and token are empty
+     */
+    Common::WebResult GenericJson(const std::string& method, const std::string& path,
+                                  const std::string& data, const std::string& jwt = "",
+                                  const std::string& username = "", const std::string& token = "") {
+        if (cli == nullptr) {
+            auto parsedUrl = LUrlParser::clParseURL::ParseURL(host);
+            int port;
+            if (parsedUrl.m_Scheme == "http") {
+                if (!parsedUrl.GetPort(&port)) {
+                    port = HTTP_PORT;
+                }
+                cli = std::make_unique<httplib::Client>(parsedUrl.m_Host.c_str(), port,
+                                                        TIMEOUT_SECONDS);
+            } else if (parsedUrl.m_Scheme == "https") {
+                if (!parsedUrl.GetPort(&port)) {
+                    port = HTTPS_PORT;
+                }
+                cli = std::make_unique<httplib::SSLClient>(parsedUrl.m_Host.c_str(), port,
+                                                           TIMEOUT_SECONDS);
+            } else {
+                LOG_ERROR(WebService, "Bad URL scheme {}", parsedUrl.m_Scheme);
+                return Common::WebResult{Common::WebResult::Code::InvalidURL, "Bad URL scheme"};
             }
-            cli = std::make_unique<httplib::SSLClient>(parsedUrl.m_Host.c_str(), port,
-                                                       TIMEOUT_SECONDS);
-        } else {
-            LOG_ERROR(WebService, "Bad URL scheme {}", parsedUrl.m_Scheme);
-            return Common::WebResult{Common::WebResult::Code::InvalidURL, "Bad URL scheme"};
         }
-    }
-    if (cli == nullptr) {
-        LOG_ERROR(WebService, "Invalid URL {}", host + path);
-        return Common::WebResult{Common::WebResult::Code::InvalidURL, "Invalid URL"};
-    }
+        if (cli == nullptr) {
+            LOG_ERROR(WebService, "Invalid URL {}", host + path);
+            return Common::WebResult{Common::WebResult::Code::InvalidURL, "Invalid URL"};
+        }
 
-    httplib::Headers params;
-    if (!jwt.empty()) {
-        params = {
-            {std::string("Authorization"), fmt::format("Bearer {}", jwt)},
-        };
-    } else if (!username.empty()) {
-        params = {
-            {std::string("x-username"), username},
-            {std::string("x-token"), token},
+        httplib::Headers params;
+        if (!jwt.empty()) {
+            params = {
+                {std::string("Authorization"), fmt::format("Bearer {}", jwt)},
+            };
+        } else if (!username.empty()) {
+            params = {
+                {std::string("x-username"), username},
+                {std::string("x-token"), token},
+            };
+        }
+
+        params.emplace(std::string("api-version"),
+                       std::string(API_VERSION.begin(), API_VERSION.end()));
+        if (method != "GET") {
+            params.emplace(std::string("Content-Type"), std::string("application/json"));
         };
-    }
 
-    params.emplace(std::string("api-version"), std::string(API_VERSION.begin(), API_VERSION.end()));
-    if (method != "GET") {
-        params.emplace(std::string("Content-Type"), std::string("application/json"));
-    };
+        httplib::Request request;
+        request.method = method;
+        request.path = path;
+        request.headers = params;
+        request.body = data;
 
-    httplib::Request request;
-    request.method = method;
-    request.path = path;
-    request.headers = params;
-    request.body = data;
+        httplib::Response response;
 
-    httplib::Response response;
+        if (!cli->send(request, response)) {
+            LOG_ERROR(WebService, "{} to {} returned null", method, host + path);
+            return Common::WebResult{Common::WebResult::Code::LibError, "Null response"};
+        }
 
-    if (!cli->send(request, response)) {
-        LOG_ERROR(WebService, "{} to {} returned null", method, host + path);
-        return Common::WebResult{Common::WebResult::Code::LibError, "Null response"};
-    }
+        if (response.status >= 400) {
+            LOG_ERROR(WebService, "{} to {} returned error status code: {}", method, host + path,
+                      response.status);
+            return Common::WebResult{Common::WebResult::Code::HttpError,
+                                     std::to_string(response.status)};
+        }
 
-    if (response.status >= 400) {
-        LOG_ERROR(WebService, "{} to {} returned error status code: {}", method, host + path,
-                  response.status);
-        return Common::WebResult{Common::WebResult::Code::HttpError,
-                                 std::to_string(response.status)};
-    }
+        auto content_type = response.headers.find("content-type");
 
-    auto content_type = response.headers.find("content-type");
+        if (content_type == response.headers.end()) {
+            LOG_ERROR(WebService, "{} to {} returned no content", method, host + path);
+            return Common::WebResult{Common::WebResult::Code::WrongContent, ""};
+        }
 
-    if (content_type == response.headers.end()) {
-        LOG_ERROR(WebService, "{} to {} returned no content", method, host + path);
-        return Common::WebResult{Common::WebResult::Code::WrongContent, ""};
+        if (content_type->second.find("application/json") == std::string::npos &&
+            content_type->second.find("text/html; charset=utf-8") == std::string::npos) {
+            LOG_ERROR(WebService, "{} to {} returned wrong content: {}", method, host + path,
+                      content_type->second);
+            return Common::WebResult{Common::WebResult::Code::WrongContent, "Wrong content"};
+        }
+        return Common::WebResult{Common::WebResult::Code::Success, "", response.body};
     }
 
-    if (content_type->second.find("application/json") == std::string::npos &&
-        content_type->second.find("text/html; charset=utf-8") == std::string::npos) {
-        LOG_ERROR(WebService, "{} to {} returned wrong content: {}", method, host + path,
-                  content_type->second);
-        return Common::WebResult{Common::WebResult::Code::WrongContent, "Wrong content"};
-    }
-    return Common::WebResult{Common::WebResult::Code::Success, "", response.body};
-}
+    // Retrieve a new JWT from given username and token
+    void UpdateJWT() {
+        if (username.empty() || token.empty()) {
+            return;
+        }
 
-void Client::UpdateJWT() {
-    if (!username.empty() && !token.empty()) {
         auto result = GenericJson("POST", "/jwt/internal", "", "", username, token);
         if (result.result_code != Common::WebResult::Code::Success) {
             LOG_ERROR(WebService, "UpdateJWT failed");
@@ -123,27 +158,39 @@ void Client::UpdateJWT() {
             jwt_cache.jwt = jwt = result.returned_data;
         }
     }
-}
 
-Common::WebResult Client::GenericJson(const std::string& method, const std::string& path,
-                                      const std::string& data, bool allow_anonymous) {
-    if (jwt.empty()) {
-        UpdateJWT();
-    }
+    std::string host;
+    std::string username;
+    std::string token;
+    std::string jwt;
+    std::unique_ptr<httplib::Client> cli;
+
+    struct JWTCache {
+        std::mutex mutex;
+        std::string username;
+        std::string token;
+        std::string jwt;
+    };
+    static inline JWTCache jwt_cache;
+};
 
-    if (jwt.empty() && !allow_anonymous) {
-        LOG_ERROR(WebService, "Credentials must be provided for authenticated requests");
-        return Common::WebResult{Common::WebResult::Code::CredentialsMissing, "Credentials needed"};
-    }
+Client::Client(std::string host, std::string username, std::string token)
+    : impl{std::make_unique<Impl>(std::move(host), std::move(username), std::move(token))} {}
 
-    auto result = GenericJson(method, path, data, jwt);
-    if (result.result_string == "401") {
-        // Try again with new JWT
-        UpdateJWT();
-        result = GenericJson(method, path, data, jwt);
-    }
+Client::~Client() = default;
+
+Common::WebResult Client::PostJson(const std::string& path, const std::string& data,
+                                   bool allow_anonymous) {
+    return impl->GenericJson("POST", path, data, allow_anonymous);
+}
+
+Common::WebResult Client::GetJson(const std::string& path, bool allow_anonymous) {
+    return impl->GenericJson("GET", path, "", allow_anonymous);
+}
 
-    return result;
+Common::WebResult Client::DeleteJson(const std::string& path, const std::string& data,
+                                     bool allow_anonymous) {
+    return impl->GenericJson("DELETE", path, data, allow_anonymous);
 }
 
 } // namespace WebService