OAuthService.cpp

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/*  SPDX-License-Identifier: GPL-2.0-or-later */
/*!********************************************************************
 
  Audacity: A Digital Audio Editor
 
  OAuthService.cpp
 
  Dmitry Vedenko
 
**********************************************************************/
 
#include "OAuthService.h"
 
#include <cassert>
#include <cctype>
 
#include <rapidjson/document.h>
#include <rapidjson/writer.h>
 
#include "CodeConversions.h"
#include "Prefs.h"
 
#include "IResponse.h"
#include "NetworkManager.h"
#include "Request.h"
 
#include "ServiceConfig.h"
 
#include "UrlDecode.h"
 
#include "BasicUI.h"
 
namespace cloud::audiocom
{
namespace
{
 
StringSetting refreshToken { L"/cloud/audiocom/refreshToken", "" };
 
const std::string_view uriPrefix = "audacity://link";
const std::string_view usernamePrefix = "username=";
const std::string_view passwordPrefix = "password=";
const std::string_view tokenPrefix = "token=";
const std::string_view authorizationCodePrefix = "authorization_code=";
 
void WriteCommonFields(
   rapidjson::Document& document, std::string_view grantType, std::string_view scope)
{
   using namespace rapidjson;
 
   document.AddMember(
      "grant_type", StringRef(grantType.data(), grantType.size()),
      document.GetAllocator());
 
   const auto clientID = GetServiceConfig().GetOAuthClientID();
   const auto clientSecret = GetServiceConfig().GetOAuthClientSecret();
 
   document.AddMember(
      "client_id",
      Value(clientID.data(), clientID.size(), document.GetAllocator()),
      document.GetAllocator());
 
   document.AddMember(
      "client_secret",
      Value(clientSecret.data(), clientSecret.size(), document.GetAllocator()),
      document.GetAllocator());
 
   document.AddMember(
      "scope", StringRef(scope.data(), scope.size()), document.GetAllocator());
}
 
bool IsPrefixed(std::string_view hay, std::string_view prefix)
{
   if (hay.length() < prefix.length())
      return false;
 
   return std::mismatch(
             prefix.begin(), prefix.end(), hay.begin(),
             [](auto a, auto b) { return a == std::tolower(b); })
             .first == prefix.end();
}
 
} // namespace
 
void OAuthService::ValidateAuth(
   std::function<void(std::string_view)> completedHandler)
{
   if (HasAccessToken() || !HasRefreshToken())
   {
      if (completedHandler)
         completedHandler(GetAccessToken());
      return;
   }
 
   AuthoriseRefreshToken(GetServiceConfig(), std::move(completedHandler));
}
 
void OAuthService::HandleLinkURI(
   std::string_view uri, std::function<void(std::string_view)> completedHandler)
{
   if (!IsPrefixed(uri, uriPrefix))
   {
      if (completedHandler)
         completedHandler({});
      return;
   }
 
   // It was observed, that sometimes link is passed as audacity://link/
   // This is valid from URI point of view, but we need to handle it separately
   const auto argsStart = uri.find("?");
 
   if (argsStart == std::string_view::npos)
   {
      if (completedHandler)
         completedHandler({});
      return;
   }
 
   // Length is handled in IsPrefixed
   auto args = uri.substr(argsStart + 1);
 
   std::string_view token;
   std::string_view username;
   std::string_view password;
   std::string_view authorizationCode;
 
   while (!args.empty())
   {
      const auto nextArg = args.find('&');
 
      const auto arg = args.substr(0, nextArg);
      args = nextArg == std::string_view::npos ? "" : args.substr(nextArg + 1);
 
      if (IsPrefixed(arg, usernamePrefix))
         username = arg.substr(usernamePrefix.length());
      else if (IsPrefixed(arg, passwordPrefix))
         password = arg.substr(passwordPrefix.length());
      else if (IsPrefixed(arg, tokenPrefix))
         token = arg.substr(tokenPrefix.length());
      else if (IsPrefixed(arg, authorizationCodePrefix))
         authorizationCode = arg.substr(authorizationCodePrefix.length());
   }
 
   // We have a prioritized list of authorization methods
   if (!authorizationCode.empty())
   {
      AuthoriseCode(
         GetServiceConfig(), authorizationCode, std::move(completedHandler));
   }
   else if (!token.empty())
   {
      AuthoriseRefreshToken(
         GetServiceConfig(), token, std::move(completedHandler));
   }
   else if (!username.empty() && !password.empty())
   {
      AuthorisePassword(
         GetServiceConfig(),
         audacity::UrlDecode(std::string(username)),
         audacity::UrlDecode(std::string(password)),
         std::move(completedHandler));
   }
   else
   {
      if (completedHandler)
         completedHandler({});
   }
}
 
void OAuthService::UnlinkAccount()
{
   std::lock_guard<std::recursive_mutex> lock(mMutex);
 
   mAccessToken.clear();
   refreshToken.Write({});
   gPrefs->Flush();
 
   // Unlink account is expected to be called only
   // on UI thread
   Publish({ {}, {}, false });
}
 
void OAuthService::AuthorisePassword(
   const ServiceConfig& config, std::string_view userName,
   std::string_view password,
   std::function<void(std::string_view)> completedHandler)
{
   using namespace rapidjson;
 
   Document document;
   document.SetObject();
 
   WriteCommonFields(document, "password", "all");
 
   document.AddMember(
      "username", StringRef(userName.data(), userName.size()),
      document.GetAllocator());
 
   document.AddMember(
      "password", StringRef(password.data(), password.size()),
      document.GetAllocator());
 
   rapidjson::StringBuffer buffer;
   rapidjson::Writer<rapidjson::StringBuffer> writer(buffer);
   document.Accept(writer);
 
   DoAuthorise(
      config, { buffer.GetString(), buffer.GetSize() },
      std::move(completedHandler));
}
 
void OAuthService::AuthoriseRefreshToken(
   const ServiceConfig& config, std::string_view token,
   std::function<void(std::string_view)> completedHandler)
{
   using namespace rapidjson;
 
   Document document;
   document.SetObject();
 
   WriteCommonFields(document, "refresh_token", "");
 
   document.AddMember(
      "refresh_token", StringRef(token.data(), token.size()),
      document.GetAllocator());
 
   rapidjson::StringBuffer buffer;
   rapidjson::Writer<rapidjson::StringBuffer> writer(buffer);
   document.Accept(writer);
 
   DoAuthorise(
      config, { buffer.GetString(), buffer.GetSize() },
      std::move(completedHandler));
}
 
void OAuthService::AuthoriseRefreshToken(
   const ServiceConfig& config,
   std::function<void(std::string_view)> completedHandler)
{
   std::lock_guard<std::recursive_mutex> lock(mMutex);
 
   AuthoriseRefreshToken(
      config, audacity::ToUTF8(refreshToken.Read()),
      std::move(completedHandler));
}
 
void OAuthService::AuthoriseCode(
   const ServiceConfig& config, std::string_view authorizationCode,
   std::function<void(std::string_view)> completedHandler)
{
   using namespace rapidjson;
 
   Document document;
   document.SetObject();
 
   WriteCommonFields(document, "authorization_code", "all");
 
   document.AddMember(
      "code", StringRef(authorizationCode.data(), authorizationCode.size()),
      document.GetAllocator());
 
   const auto redirectURI = config.GetOAuthRedirectURL();
 
   document.AddMember(
      "redirect_uri", StringRef(redirectURI.data(), redirectURI.size()),
      document.GetAllocator());
 
   rapidjson::StringBuffer buffer;
   rapidjson::Writer<rapidjson::StringBuffer> writer(buffer);
   document.Accept(writer);
 
   DoAuthorise(
      config, { buffer.GetString(), buffer.GetSize() },
      std::move(completedHandler));
}
 
bool OAuthService::HasAccessToken() const
{
   return !GetAccessToken().empty();
}
 
bool OAuthService::HasRefreshToken() const
{
   std::lock_guard<std::recursive_mutex> lock(mMutex);
   return !refreshToken.Read().empty();
}
 
std::string OAuthService::GetAccessToken() const
{
   std::lock_guard<std::recursive_mutex> lock(mMutex);
   
   if (Clock::now() < mTokenExpirationTime)
      return mAccessToken;
 
   return {};
}
 
void OAuthService::DoAuthorise(
   const ServiceConfig& config, std::string_view payload,
   std::function<void(std::string_view)> completedHandler)
{
   using namespace audacity::network_manager;
 
   Request request(config.GetAPIUrl("/auth/token"));
 
   request.setHeader(
      common_headers::ContentType, common_content_types::ApplicationJson);
   
   request.setHeader(
      common_headers::Accept, common_content_types::ApplicationJson);
 
   auto response = NetworkManager::GetInstance().doPost(
      request, payload.data(), payload.size());
 
   response->setRequestFinishedCallback(
      [response, this, handler = std::move(completedHandler)](auto)
      {
         const auto httpCode = response->getHTTPCode();
         const auto body = response->readAll<std::string>();
 
         if (httpCode != 200)
         {
            if (handler)
               handler({});
 
            // Token has expired?
            if (httpCode == 422)
               BasicUI::CallAfter([this] { UnlinkAccount(); });
            else            
               SafePublish({ {}, body, false });
            
            return;
         }
 
         rapidjson::Document document;
         document.Parse(body.data(), body.size());
 
         if (!document.IsObject())
         {
            if (handler)
               handler({});
            
            SafePublish({ {}, body, false });
            return;
         }
 
         const auto tokenType = document["token_type"].GetString();
         const auto accessToken = document["access_token"].GetString();
         const auto expiresIn = document["expires_in"].GetInt64();
         const auto newRefreshToken = document["refresh_token"].GetString();
 
         {
            std::lock_guard<std::recursive_mutex> lock(mMutex);
 
            mAccessToken = std::string(tokenType) + " " + accessToken;
            mTokenExpirationTime =
               Clock::now() + std::chrono::seconds(expiresIn);
         }
 
         BasicUI::CallAfter(
            [token = std::string(newRefreshToken)]()
            {
               // At this point access token is already written,
               // only refresh token is updated.
               refreshToken.Write(token);
               gPrefs->Flush();
            });
 
         if (handler)
            handler(mAccessToken);
 
         // The callback only needs the access token, so invoke it immediately.
         // Networking is thread safe
         SafePublish({ mAccessToken, {}, true });
      });
}
 
void OAuthService::SafePublish(const AuthStateChangedMessage& message)
{
   BasicUI::CallAfter([this, message]() { Publish(message); });
}
 
OAuthService& GetOAuthService()
{
   static OAuthService service;
   return service;
}
} // namespace cloud::audiocom