/// <inheritdoc />
public override async Task <Uri?> GetNextPageLinkAsync(PageLinkData pageLinkData, CancellationToken cancellationToken = default)
{
if (IsJson(pageLinkData) && pageLinkData.Response != null)
{
try
{
using var doc = await JsonDocument.ParseAsync(pageLinkData.Response, cancellationToken : cancellationToken);
var hasNextLink = doc.RootElement.TryGetProperty(pageLinkData.NextLinkName, out var nextLink);
if (hasNextLink && nextLink.ValueKind == JsonValueKind.String)
{
string?link = nextLink.GetString();
if (!string.IsNullOrWhiteSpace(link))
{
return(new Uri(link));
}
}
}
catch (JsonException)
{
// If the response isn't valid JSON, there will be no next link.
// TODO: Log warning once logging story is defined
}
}
return(null);
}
/// <inheritdoc />
public override async Task <Stream?> MergePageAsync(Stream?currentResult, PageLinkData newPageData, CancellationToken cancellationToken = default)
{
if (IsJson(newPageData))
{
return(await MergeJsonStreamsAsync(currentResult, newPageData.Response, newPageData.ItemName, newPageData.NextLinkName, cancellationToken));
}
return(null);
}
public async Task Return_Null_on_No_Next_Link()
{
var pagingService = new ODataPagingService();
var requestInfo = new RequestInformation();
var pagingData = new PageLinkData(requestInfo, null);
var nextLink = await pagingService.GetNextPageLinkAsync(pagingData);
Assert.Null(nextLink);
}
public async Task Return_Null_On_Next_Link_Missing()
{
var pagingService = new ODataPagingService();
var bytes = Encoding.UTF8.GetBytes("{}");
using var ms = new MemoryStream(bytes);
var requestInfo = new RequestInformation();
var pagingData = new PageLinkData(requestInfo, ms);
var nextLink = await pagingService.GetNextPageLinkAsync(pagingData);
Assert.Null(nextLink);
}
public async Task Return_Next_Link_From_Response()
{
var pagingService = new ODataPagingService();
var bytes = Encoding.UTF8.GetBytes("{\"nextLink\": \"https://testlink\"}");
using var ms = new MemoryStream(bytes);
var requestInfo = new RequestInformation();
requestInfo.Headers.Add("Accept", "application/json");
var pagingData = new PageLinkData(requestInfo, ms);
pagingData.ResponseContentHeaders.Add("Content-Type", new string[] { "application/json" });
var nextLink = await pagingService.GetNextPageLinkAsync(pagingData);
Assert.Equal(new Uri("https://testlink"), nextLink);
}
/// <inheritdoc />
public virtual async Task <PageResponse?> GetPagedDataAsync(Func <RequestInformation, IResponseHandler, CancellationToken, Task> requestExecutorAsync, PageLinkData pageLinkData, bool fetchAllPages = false, CancellationToken cancellationToken = default)
{
if (!OnBeforeGetPagedData(pageLinkData, fetchAllPages))
{
return(null);
}
var requestInfo = pageLinkData.RequestInformation;
Uri? nextLink;
Stream?response = null;
int? statusCode;
do
{
var responseHandler = CreateResponseHandler();
await requestExecutorAsync(requestInfo, responseHandler, cancellationToken);
var pageData = await responseHandler.GetResponseStreamAsync(cancellationToken);
statusCode = responseHandler.GetStatusCode();
var headers = responseHandler.GetResponseHeaders();
var contentHeaders = responseHandler.GetResponseContentHeaders();
pageLinkData = new PageLinkData(requestInfo, pageData, headers, contentHeaders, pageLinkData.ItemName, pageLinkData.NextLinkName);
if (fetchAllPages)
{
nextLink = await GetNextPageLinkAsync(pageLinkData, cancellationToken);
if (nextLink != null)
{
pageLinkData.RequestInformation.URI = nextLink;
}
}
else
{
nextLink = null;
}
response = await MergePageAsync(response, pageLinkData, cancellationToken);
} while (nextLink != null);
return(new PageResponse(statusCode ?? 0, response));
}
private bool IsJson(PageLinkData pageLinkData)
{
return(pageLinkData.ResponseContentHeaders.TryGetValue("Content-Type", out var contentType) && contentType.Any(c => c.Contains("json")));
}
/// <inheritdoc />
public override bool OnBeforeGetPagedData(PageLinkData pageLinkData, bool fetchAllPages = false)
{
return(true);
}
/// <inheritdoc />
public virtual bool OnBeforeGetPagedData(PageLinkData pageLinkData, bool fetchAllPages = false)
{
return(true);
}
/// <inheritdoc /> public abstract Task <Stream?> MergePageAsync(Stream?currentResult, PageLinkData newPageData, CancellationToken cancellationToken = default);
/// <inheritdoc /> public abstract Task <Uri?> GetNextPageLinkAsync(PageLinkData pageLinkData, CancellationToken cancellationToken = default);