C# HttpClient設置cookies的兩種辦法

通常有兩種辦法

第一種handler.UseCookies=true(默認爲true)，默認的會本身帶上cookies，例如

var handler = new HttpClientHandler() { UseCookies = true };
var client = new HttpClient(handler);// { BaseAddress = baseAddress };
client.DefaultRequestHeaders.Add("user-agent", "Mozilla/5.0 (Windows NT 6.1; Win64; x64; rv:57.0) Gecko/20100101 Firefox/57.0");
client.DefaultRequestHeaders.Add("Connection", "Keep-Alive");
client.DefaultRequestHeaders.Add("Keep-Alive", "timeout=600");
var content = new FormUrlEncodedContent(new[]
            {
                new KeyValuePair<string, string>("email", "xxxx"),
                new KeyValuePair<string, string>("password", "xxxx"),
            });
var result = await client.PostAsync("https://www.xxxx.com/cp/login", content);
result.EnsureSuccessStatusCode();

這種狀況post請求登錄成功後，重定向到別的頁面，也會自動帶上cookies。若是把handler.UseCookies設置爲false，登錄後重定向的話不會自動帶上cookies，則又會跳轉到登錄頁面。

 

第二種設置 handler.UseCookies = false時，則須要手動給headers上加入cookies.

var handler = new HttpClientHandler() { UseCookies = false};
var client = new HttpClient(handler);// { BaseAddress = baseAddress };
var message = new HttpRequestMessage(HttpMethod.Get, url);
message.Headers.Add("Cookie", "session_id=7258abbd1544b6c530a9f406d3e600239bd788fb");
var result = await client.SendAsync(message);
result.EnsureSuccessStatusCode();

若是使用場景是：抓取須要登錄後才能看到的網頁數據，建議使用第一種，不須要設置任何cookies，httpclient會自動把登錄後的cookies放置到後面的請求中。