GetAsync for fbcdn返回403禁止？
注意：我已经改变了这个问题，试图让它更多地指出问题。 下面的评论不再反映这个问题。
我试图从fbcdn获取这个图像：
https://scontent.xx.fbcdn.net/v/t1.0-1/c15.0.50.50/p50x50/10354686_10150004552801856_220367501106153455_n.jpg?oh=6c801f82cd5a32fd6e5a4258ce00a314&oe=589AAD2F
浏览器得到它很好。 这是我的代码：
public class ReverseProxyController : NancyModule
{
public ReverseProxyController()
{
Get["/", true] = async (parameters, ct) =>
{
var result = await GetResult(parameters, ct);
return result;
};
}
private async Task<Response> GetResult(dynamic parameters, CancellationToken ct)
{
var client = new HttpClient();
string url = Request.Query["url"].Value.ToString();
if (url == null) return null;
client.DefaultRequestHeaders.Add("Access-Control-Allow-Origin", "*");
client.DefaultRequestHeaders.Add("User-Agent",
"Mozilla/5.0 (Windows NT 6.1; WOW64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/54.0.2840.71 Safari/537.36");
client.DefaultRequestHeaders.Add("Upgrade-Insecure-Requests", "1");
client.DefaultRequestHeaders.Add("Accept", "text/html,application/xhtml+xml,application/xml;q=0.9,image/webp,*/*;q=0.8");
client.DefaultRequestHeaders.Add("Accept-Encoding", "gzip, deflate, sdch, br");
client.DefaultRequestHeaders.Add("Accept-Language", "en-US,en;q=0.8,ru;q=0.6");
var response = await client.GetAsync(url, ct);
ct.ThrowIfCancellationRequested();
switch (response.StatusCode)
{
case HttpStatusCode.OK:
var stream = await response.Content.ReadAsStreamAsync();
return Response.FromStream(stream, response.Content.Headers.ContentType != null
? response.Content.Headers.ContentType.ToString()
: "application/octet-stream");
default:
return Response.AsText("nError " + response.StatusCode);
}
}
}
我每次都得到403禁止回复。 我认为添加标题会使它工作，但不行。
此代码适用于其他主机上的其他图像，例如：
https://s-media-cache-ak0.pinimg.com/564x/ff/f0/c9/fff0c988a4516659d4009f60e0694cb6.jpg
问题在于从南希请求的URL检索，而不是使用HttpClient获取数据。
我假设你正在向南非发送请求，如：
HTTP：//本地主机/ URL = ...
因此对于Facebook来说，这将是：
HTTP：//本地主机/ URL = HTTPS：//scontent.xx.fbcdn.net/v/t1.0-1/c15.0.50.50/p50x50/10354686_10150004552801856_220367501106153455_n.jpg哦= 6c801f82cd5a32fd6e5a4258ce00a314＆OE = 589AAD2F
但是对于这个url string url = Request.Query["url"].Value.ToString(); 是不完整的，并且遗漏了最后一部分（＆oe = 589AAD2F），因此服务器对Forbidden进行响应。
以下是演示问题的简单更改：
private async Task<Response> GetResult(dynamic parameters, CancellationToken ct)
{
var client = new HttpClient();
var req = Request.Url.ToString();
var queryStart = req.IndexOf("url=");
if (queryStart == -1)
return Nancy.HttpStatusCode.BadRequest;
var url = req.Substring(queryStart + 4);
if (string.IsNullOrEmpty(url))
return Nancy.HttpStatusCode.BadRequest;
client.DefaultRequestHeaders.Add("Access-Control-Allow-Origin", "*");
client.DefaultRequestHeaders.Add("User-Agent",
"Mozilla/5.0 (Windows NT 6.1; WOW64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/54.0.2840.71 Safari/537.36");
client.DefaultRequestHeaders.Add("Upgrade-Insecure-Requests", "1");
client.DefaultRequestHeaders.Add("Accept", "text/html,application/xhtml+xml,application/xml;q=0.9,image/webp,*/*;q=0.8");
client.DefaultRequestHeaders.Add("Accept-Encoding", "gzip, deflate, sdch, br");
client.DefaultRequestHeaders.Add("Accept-Language", "en-US,en;q=0.8,ru;q=0.6");
var response = await client.GetAsync(url, ct);
ct.ThrowIfCancellationRequested();
switch (response.StatusCode)
{
case System.Net.HttpStatusCode.OK:
var stream = await response.Content.ReadAsStreamAsync();
return Response.FromStream(stream, response.Content.Headers.ContentType != null
? response.Content.Headers.ContentType.ToString()
: "application/octet-stream");
default:
return Response.AsText("nError " + response.StatusCode);
}
}
解
我们实际上可以在发送URL之前对URL进行编码，Nancy会自动为我们解码URL，因此不需要更改任何服务器端的内容。
这是一个使用HttpUtility.UrlEncode生成的链接示例
https://scontent.xx.fbcdn.net/v/t1.0-1/c15.0.50.50/p50x50/10354686_10150004552801856_220367501106153455_n.jpg?oh=6c801f82cd5a32fd6e5a4258ce00a314&oe=589AAD2F
结果：
HTTPS％3A％2F％2fscontent.xx.fbcdn.net％2FV％2ft1.0-1％2fc15.0.50.50％2fp50x50％2f10354686_10150004552801856_220367501106153455_n.jpg％3foh％3d6c801f82cd5a32fd6e5a4258ce00a314％26oe％3d589AAD2F
并且对于这个特定链接的实际请求将是：
HTTP：//本地主机：9876 / URL = HTTPS％3A％2F％2fscontent.xx.fbcdn.net％2FV％2ft1.0-1％2fc15.0.50.50％2fp50x50％2f10354686_10150004552801856_220367501106153455_n.jpg％3foh％3d6c801f82cd5a32fd6e5a4258ce00a314％26oe ％3d589AAD2F
替代解决方案
在这种情况下，我个人更喜欢POST over GET，所以这里是：
public class ReverseProxyController : NancyModule
{
class ProxyRequest
{
public string Url { get; set; }
}
public ReverseProxyController()
{
Post["/", true] = async (parameters, ct) =>
{
var result = await GetResult(parameters, ct);
return result;
};
}
private async Task<Response> GetResult(dynamic parameters, CancellationToken ct)
{
var pReq = this.Bind<ProxyRequest>();
var url = pReq.Url;
if (string.IsNullOrEmpty(url))
return null;
var client = new HttpClient();
client.DefaultRequestHeaders.Add("Access-Control-Allow-Origin", "*");
client.DefaultRequestHeaders.Add("User-Agent",
"Mozilla/5.0 (Windows NT 6.1; WOW64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/54.0.2840.71 Safari/537.36");
client.DefaultRequestHeaders.Add("Upgrade-Insecure-Requests", "1");
client.DefaultRequestHeaders.Add("Accept", "text/html,application/xhtml+xml,application/xml;q=0.9,image/webp,*/*;q=0.8");
client.DefaultRequestHeaders.Add("Accept-Encoding", "gzip, deflate, sdch, br");
client.DefaultRequestHeaders.Add("Accept-Language", "en-US,en;q=0.8,ru;q=0.6");
var response = await client.GetAsync(url, ct);
ct.ThrowIfCancellationRequested();
switch (response.StatusCode)
{
case System.Net.HttpStatusCode.OK:
var stream = await response.Content.ReadAsStreamAsync();
return Response.FromStream(stream, response.Content.Headers.ContentType != null
? response.Content.Headers.ContentType.ToString()
: "application/octet-stream");
default:
return Response.AsText("nError " + response.StatusCode);
}
}
}
作为控制台应用程序，您的代码工作正常
static void Main(string[] args)
{
GetStuff();
Console.ReadLine();
}
private static async void GetStuff()
{
CancellationToken ct = new CancellationToken();
var client = new HttpClient();
//this is only a Simple Change to demonstrate the problem, and should not be considered as a proper solution
string url = "https://scontent.xx.fbcdn.net/v/t1.0-1/c15.0.50.50/p50x50/10354686_10150004552801856_220367501106153455_n.jpg?oh=6c801f82cd5a32fd6e5a4258ce00a314&oe=589AAD2F";
if (url == null) return;
client.DefaultRequestHeaders.Add("Access-Control-Allow-Origin", "*");
client.DefaultRequestHeaders.Add("User-Agent",
"Mozilla/5.0 (Windows NT 6.1; WOW64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/54.0.2840.71 Safari/537.36");
client.DefaultRequestHeaders.Add("Upgrade-Insecure-Requests", "1");
client.DefaultRequestHeaders.Add("Accept", "text/html,application/xhtml+xml,application/xml;q=0.9,image/webp,*/*;q=0.8");
client.DefaultRequestHeaders.Add("Accept-Encoding", "gzip, deflate, sdch, br");
client.DefaultRequestHeaders.Add("Accept-Language", "en-US,en;q=0.8,ru;q=0.6");
var response = await client.GetAsync(url, ct);
ct.ThrowIfCancellationRequested();
switch (response.StatusCode)
{
case System.Net.HttpStatusCode.OK:
var stream = await response.Content.ReadAsStreamAsync();
break;
default:
break;
}
}
我得到一个OK 200返回消息。 它使用的其他图像可能需要登录信息吗？
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