private string CreateUnsignedRequest(RequestParametersModel requestParametersModel)
{
_logger.Info("Start creatting unsigned request.");
_logger.Info("Getting AWSAccessKeyIdPublic and AssociateTag values from section: appSettings of web.config.");
string awsAccessKeyIdPublic = Settings.Default.AWSAccessKeyIdPublic;
string associateTag = Settings.Default.AssociateTag;
var timeStamp = DateTime.UtcNow.AddDays(1).ToString("yyyy-MM-ddT12:00:00.000Z");
_logger.Info("Creatting collection of parameters using to compose request.");
var parameters = new SortedDictionary <string, string>(new StringComparerByByte())
{
{ "Service", "AWSECommerceService" },
{ "AWSAccessKeyId", $"{awsAccessKeyIdPublic}" },
{ "AssociateTag", $"{associateTag}" },
{ "Operation", "ItemSearch" },
{ "SearchIndex", "Electronics" },
{ "BrowseNode", "493964" }, // 172282 493964 2102313011
{ "ResponseGroup", "Images,ItemAttributes,OfferSummary,BrowseNodes" },
{ "Availability", "Available" },
{ "Condition", "New" },
{ "MinPercentageOff", "10" },
{ "MinimumPrice", $"{requestParametersModel.MinPrice}" },
{ "MaximumPrice", $"{requestParametersModel.MaxPrice}" },
{ "Sort", "price" },
{ "ItemPage", $"{requestParametersModel.Page}" },
{ "Timestamp", $"{timeStamp}" }
};
// Parameters with percent-encoding values. See RFC 3986 Section 2.1.
var parametersEncoded = new Dictionary <string, string>();
var regex = new Regex(@"%[a-f0-9]{2}");
_logger.Info("Replacing specific signs to percent-encoding.");
foreach (var p in parameters)
{
var key = p.Key;
var valueLower = HttpUtility.UrlEncode(p.Value);
var value = regex.Replace(valueLower, n => n.Value.ToUpperInvariant());
parametersEncoded.Add(key, value);
}
var unsignedRequest = new StringBuilder();
_logger.Info($"Creatting {nameof(unsignedRequest)} that contains key=value pairs that have been divided via sign &.");
foreach (var p in parametersEncoded)
{
unsignedRequest.Append($"{p.Key}={p.Value}&");
}
_logger.Info($"{nameof(unsignedRequest)} has been created successfully.");
return(unsignedRequest.ToString().TrimEnd('&'));
}
/// <inheritdoc />
public string CreateSignedRequest(RequestParametersModel requestParametersModel)
{
// Creating unsigned request string.
var unsignedRequest = this.CreateUnsignedRequest(requestParametersModel);
_logger.Info("Start creatting signed request.");
// Endpoint for US server.
const string endpoint = "http://webservices.amazon.com/onca/xml?";
_logger.Info("Creatting request to sign.");
var requestToSign = "GET\n" +
"webservices.amazon.com\n" +
"/onca/xml\n" +
unsignedRequest;
_logger.Info("Getting AWSAccessKeyIdPrivate value from section: appSettings of web.config.");
string awsAccessKeyIdPrivate = Settings.Default.AWSAccessKeyIdPrivate;
_logger.Info($"Converting {nameof(awsAccessKeyIdPrivate)} and {nameof(requestToSign)} " +
$"to byte's array.");
var secretKeyBytes = new ASCIIEncoding().GetBytes(awsAccessKeyIdPrivate);
var unsignedRequestBytes = new ASCIIEncoding().GetBytes(requestToSign);
_logger.Info("Encrypting string with secret key.");
var signatureBytes = new HMACSHA256(secretKeyBytes)
.ComputeHash(unsignedRequestBytes);
// Recommendation from Amazon's helper page.
var signature = Convert.ToBase64String(signatureBytes);
var signatureEncodedLower = HttpUtility.UrlEncode(signature);
_logger.Info("Replacing specific signs to percent-encoding.");
var regex = new Regex(@"%[a-f0-9]{2}");
var signatureEncoded = regex.Replace(signatureEncodedLower, n => n.Value.ToUpperInvariant());
_logger.Info("Composing the signed request.");
var signedRequest = endpoint +
unsignedRequest +
$"&Signature={signatureEncoded}";
_logger.Info($"{nameof(signedRequest)} has been created successfully.");
return(signedRequest);
}
/// <inheritdoc />
public async Task <IReadOnlyCollection <GoodDomainModel> > GetItemInfoByUrlAsync(RequestParametersModel requestParametersModel)
{
var signedRequest = this._signedRequestCreatorService.CreateSignedRequest(requestParametersModel);
//await Task.Delay(1000);
string responseMessage;
using (var client = new HttpClient())
{
responseMessage = await client.GetStringAsync(signedRequest);
}
return(this.Parse(responseMessage));
}
/// <inheritdoc />
public async Task AddGoodsAsync(int minPrice)
{
// Looping with step that equals to 500 (5.00 dollar).
for (; minPrice <= 50_000; minPrice += 500)
{
// Dividing price range into five equal ranges (step 50 or 0.5 dollar).
for (int page = 1, minPriceDivide = minPrice, maxPrice = minPrice + 50;
page <= 10;
page++, minPriceDivide += 50, maxPrice += 50)
{
var requestParametersModel = new RequestParametersModel
{
Page = page,
MinPrice = minPriceDivide,
MaxPrice = maxPrice
};
try
{
// Validating instance of type RequestParametersModel.
this._requestParametersModelValidator.ValidateAndThrow(requestParametersModel);
}
catch (ValidationException ex)
{
throw new ArgumentException($"Error when validating {requestParametersModel}.", ex);
}
// Getting good's info from server and adding to collection.
IReadOnlyCollection <GoodDomainModel> goodDomainModels;
try
{
goodDomainModels = await this._amazonAdapter.GetItemInfoByUrlAsync(requestParametersModel);
}
catch (HttpRequestException ex)
{
throw new ArgumentException("Error when getting data from api server.", ex);
}
if (!goodDomainModels.Any())
{
continue;
}
// Checking if good already exist into database.
// Creating new collection without duplicates.
var goodDomainModelsDeletedDuplicates = await this.CheckExistenceGoodInDb(goodDomainModels);
// Checking if category already exist into database.
// Creating new collection without duplicates.
IReadOnlyCollection <CategoryDomainModel> categoryDomainModelsDeletedDuplicates =
await this.CheckExistenceCategoryInDb(goodDomainModels.SelectMany(g => g.CategoryIdsOnShop));
// Adding collection of goods to database.
if (goodDomainModelsDeletedDuplicates.Any())
{
// Adding collection of categories to database.
if (categoryDomainModelsDeletedDuplicates.Any())
{
await this._categoryService.CreateCategoriesAsync(
categoryDomainModelsDeletedDuplicates,
goodDomainModelsDeletedDuplicates.First().ShopName);
}
await this._goodService.CreateAsync(goodDomainModelsDeletedDuplicates);
}
}
}
}
public IActionResult QuarterlyReport(RequestParametersModel parameters)
{
return(new ObjectResult(_getQuarterlyReport.GetDataSet(parameters)));
}
public IActionResult UpdateChart(RequestParametersModel parameters)
{
var dateSummaryModels = _getTimeSeries.GetDataSet(parameters);
return(new ObjectResult(dateSummaryModels));
}
