File indexing completed on 2024-05-12 05:09:27

 /***************************************************************************
     Copyright (C) 2007-2020 Robby Stephenson <robby@periapsis.org>
  ***************************************************************************/
 
 /***************************************************************************
  *                                                                         *
  *   This program is free software; you can redistribute it and/or         *
  *   modify it under the terms of the GNU General Public License as        *
  *   published by the Free Software Foundation; either version 2 of        *
  *   the License or (at your option) version 3 or any later version        *
  *   accepted by the membership of KDE e.V. (or its successor approved     *
  *   by the membership of KDE e.V.), which shall act as a proxy            *
  *   defined in Section 14 of version 3 of the license.                    *
  *                                                                         *
  *   This program is distributed in the hope that it will be useful,       *
  *   but WITHOUT ANY WARRANTY; without even the implied warranty of        *
  *   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the         *
  *   GNU General Public License for more details.                          *
  *                                                                         *
  *   You should have received a copy of the GNU General Public License     *
  *   along with this program.  If not, see <http://www.gnu.org/licenses/>. *
  *                                                                         *
  ***************************************************************************/
 
 #include "amazonrequest.h"
 #include "../tellico_debug.h"
 
 #include <QDateTime>
 #include <QCryptographicHash>
 #include <QMessageAuthenticationCode>
 
 namespace {
   static const char* AMAZON_REQUEST = "aws4_request";
   static const char* AMAZON_REQUEST_ALGORITHM = "AWS4-HMAC-SHA256";
   static const char* AMAZON_REQUEST_NAMESPACE = "com.amazon.paapi5";
   static const char* AMAZON_REQUEST_VERSION = "v1";
   static const char* AMAZON_REQUEST_SERVICE = "ProductAdvertisingAPI";
 }
 
 using Tellico::Fetch::AmazonRequest;
 
 AmazonRequest::AmazonRequest(const QString& accessKey_, const QString& secretKey_)
     : m_accessKey(accessKey_.toUtf8())
     , m_secretKey(secretKey_.toUtf8())
     , m_method("POST")
     , m_service(AMAZON_REQUEST_SERVICE)
     , m_operation(SearchItems) {
   m_amzDate = QDateTime::currentDateTimeUtc().toString(QStringLiteral("yyyyMMdd'T'hhmmss'Z'")).toUtf8();
 }
 
 void AmazonRequest::setHost(const QByteArray& host_) {
   m_host = host_;
 }
 
 void AmazonRequest::setPath(const QByteArray& path_) {
   m_path = path_;
 }
 
 void AmazonRequest::setRegion(const QByteArray& region_) {
   m_region = region_;
 }
 
 void AmazonRequest::setOperation(int op_) {
   m_operation = static_cast<Operation>(op_);
 }
 
 QMap<QByteArray, QByteArray> AmazonRequest::headers(const QByteArray& payload_) {
   m_headers.insert("content-encoding", "amz-1.0");
   m_headers.insert("content-type", "application/json; charset=utf-8");
   m_headers.insert("host", m_host);
   m_headers.insert("x-amz-date", m_amzDate);
   m_headers.insert("x-amz-target", targetOperation());
 
   const QByteArray canonicalURL = prepareCanonicalRequest(payload_);
   const QByteArray stringToSign = prepareStringToSign(canonicalURL);
   const QByteArray signature = calculateSignature(stringToSign);
   m_headers.insert("Authorization", buildAuthorizationString(signature));
   return m_headers;
 }
 
 QByteArray AmazonRequest::prepareCanonicalRequest(const QByteArray& payload_) const {
   Q_ASSERT(!m_method.isEmpty());
   Q_ASSERT(!m_path.isEmpty());
   Q_ASSERT(!m_headers.isEmpty());
   QByteArray req = m_method + '\n'
                  + m_path + '\n' + '\n';
 
   m_signedHeaders.clear();
   // a map so that the query elements are sorted
   QMapIterator<QByteArray, QByteArray> i(m_headers);
   while(i.hasNext()) {
     i.next();
 
     m_signedHeaders.append(i.key());
     m_signedHeaders.append(';');
 
     req.append(i.key());
     req.append(':');
     req.append(i.value());
     req.append('\n');
   }
   req.append('\n');
 
   m_signedHeaders.chop(1); // remove final ';'
   req.append(m_signedHeaders);
   req.append('\n');
 
   req.append(toHexHash(payload_));
   return req;
 }
 
 QByteArray AmazonRequest::prepareStringToSign(const QByteArray& canonicalUrl_) const {
   QByteArray stringToSign(AMAZON_REQUEST_ALGORITHM);
   stringToSign += '\n';
   stringToSign += m_amzDate + '\n';
   stringToSign += m_amzDate.left(8) + '/' + m_region + '/' + m_service + '/' + AMAZON_REQUEST + '\n';
   stringToSign += toHexHash(canonicalUrl_);
   return stringToSign;
 }
 
 QByteArray AmazonRequest::calculateSignature(const QByteArray& stringToSign_) const {
   QByteArray signatureKey;
   signatureKey = QMessageAuthenticationCode::hash(m_amzDate.left(8), "AWS4" + m_secretKey, QCryptographicHash::Sha256);
   signatureKey = QMessageAuthenticationCode::hash(m_region, signatureKey, QCryptographicHash::Sha256);
   signatureKey = QMessageAuthenticationCode::hash(m_service, signatureKey, QCryptographicHash::Sha256);
   signatureKey = QMessageAuthenticationCode::hash(AMAZON_REQUEST, signatureKey, QCryptographicHash::Sha256);
   // '0' says no separators between hex encoded characters
   return QMessageAuthenticationCode::hash(stringToSign_, signatureKey, QCryptographicHash::Sha256).toHex(0);
 }
 
 QByteArray AmazonRequest::buildAuthorizationString(const QByteArray& signature_) const {
   Q_ASSERT(!m_accessKey.isEmpty());
   Q_ASSERT(!m_region.isEmpty());
   Q_ASSERT(!m_service.isEmpty());
   Q_ASSERT(!m_signedHeaders.isEmpty());
   QByteArray authString(AMAZON_REQUEST_ALGORITHM);
   authString += ' ';
   authString += "Credential=" + m_accessKey;
   authString += '/' + m_amzDate.left(8) + '/' + m_region + '/' + m_service + "/" + AMAZON_REQUEST + ", ";
   authString += "SignedHeaders=" + m_signedHeaders + ", " + "Signature=" + signature_;
   return authString;
 }
 
 QByteArray AmazonRequest::toHexHash(const QByteArray& data_) const {
   const QByteArray hash = QCryptographicHash::hash(data_, QCryptographicHash::Sha256);
   return hash.toHex(0); // '0' says no separators between hex encoded characters
 }
 
 QByteArray AmazonRequest::targetOperation() const {
   QByteArray target(AMAZON_REQUEST_NAMESPACE);
   target.append('.');
   target.append(AMAZON_REQUEST_VERSION);
   target.append('.');
   target.append(m_service);
   target.append(AMAZON_REQUEST_VERSION);
   target.append('.');
   switch(m_operation) {
     case SearchItems:
       target.append("SearchItems");
       break;
     case GetItems:
       target.append("GetItems");
       break;
   }
   return target;
 }