/// <summary>
/// Wraps a <see cref="IResponseMessageCacheEntry"/> object as a <see cref="ResponseMessageCacheEntry"/>.
/// </summary>
public static async Task <ResponseMessageCacheEntry> WrapAsync(IResponseMessageCacheEntry entry)
{
var result = entry as ResponseMessageCacheEntry;
if (result == null)
{
result = await CreateAsync(entry.ETag, entry.LastModified, entry.ToResponseMessage());
}
return(result);
}
/// <inheritdoc />
public Task <IResponseMessageCacheEntry> GetAsync(Uri requestUri)
{
IResponseMessageCacheEntry result = null;
if (cacheNode.Key == requestUri)
{
result = cacheNode.Value;
}
return(Task.FromResult(result));
}
private async Task <IPageCollection <T> > GetPageCollectionAsync <T>(Uri uri, string accessToken, CancellationToken cancellationToken)
{
IResponseMessageCacheEntry responseMessageCacheEntry = null;
if (responseMessageCache != null)
{
responseMessageCacheEntry = await responseMessageCache.GetAsync(uri);
}
await rateLimiter.WaitIfNecessaryAsync();
string responseJson;
Uri nextUri;
using (var requestMessage = CreateRequest(HttpMethod.Get, uri, accessToken: accessToken, responseMessageCacheEntry: responseMessageCacheEntry))
using (var httpClient = httpClientPool.Create())
using (var responseMessage = await httpClient.SendAsync(requestMessage, cancellationToken))
{
var localResponseMessage = responseMessage;
if (responseMessage.StatusCode == System.Net.HttpStatusCode.NotModified && responseMessageCacheEntry != null)
{
localResponseMessage = responseMessageCacheEntry.ToResponseMessage();
}
else
{
await HttpResponseUtils.EnsureSuccessAsync(responseMessage);
}
responseJson = await localResponseMessage.Content.ReadAsStringAsync();
nextUri = HttpResponseUtils.ParseNextUriOrNull(localResponseMessage);
if (responseMessageCacheEntry == null)
{
await CacheResponseMessageAsync(uri, localResponseMessage, responseJson);
}
}
var elements = JsonConvert.DeserializeObject <IReadOnlyCollection <T> >(responseJson);
return(new PageCollection <T>(elements, nextUri, this));
}
private HttpRequestMessage CreateRequest(HttpMethod method, Uri requestUri, string accessToken, IResponseMessageCacheEntry responseMessageCacheEntry)
{
var requestMessage = new HttpRequestMessage(method, requestUri);
requestMessage.Headers.UserAgent.TryParseAdd(userAgent);
if (accessToken != null)
{
requestMessage.Headers.Authorization = new AuthenticationHeaderValue("Bearer", accessToken);
}
if (responseMessageCache != null)
{
if (!string.IsNullOrWhiteSpace(responseMessageCacheEntry.ETag))
{
requestMessage.Headers.IfNoneMatch.TryParseAdd(responseMessageCacheEntry.ETag);
}
if (responseMessageCacheEntry.LastModified.HasValue)
{
requestMessage.Headers.IfModifiedSince = responseMessageCacheEntry.LastModified;
}
}
return(requestMessage);
}
/// <inheritdoc />
public async Task SetAsync(Uri requestUri, IResponseMessageCacheEntry responseMessageCacheEntry)
{
var cacheValue = await ResponseMessageCacheEntry.WrapAsync(responseMessageCacheEntry);
cacheNode = new KeyValuePair <Uri, ResponseMessageCacheEntry>(requestUri, cacheValue);
}
