閑來無事，寫了一個對discuss論壇登錄的案例，初次上場按照以前的慣例沒成功，見過抓包分析discuss論壇成功完成，廢話不多說 直接上代碼。

1：winform 做客戶端，添加HttpClient的引用

初始化對象：

private const string BaseUrl = "替換為論壇地址";
        private const string useAgent = "Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/74.0.3729.131 Safari/537.36
 
";
        private readonly HttpClient httpClient;
        private readonly HttpClientHandler handler;
        private readonly string userName = "superadmin";
        private readonly string passWord = "123456";
        private readonly HtmlDocument htmlDoc;
        private BaiDuToken baiDuToken;
        
 
public Form1()
        {
            InitializeComponent();
            handler = new HttpClientHandler() { UseCookies = true, AllowAutoRedirect = true };
            httpClient = new HttpClient(handler) { BaseAddress = new Uri(BaseUrl) };
            httpClient.DefaultRequestHeaders.Add("user-agent
 
", useAgent);
            httpClient.DefaultRequestHeaders.Add("Connection", "Keep-Alive");
            httpClient.DefaultRequestHeaders.Add("Keep-Alive", "timeout=600");
            httpClient.DefaultRequestHeaders.Add("Referer", $"{BaseUrl}member.php?mod=logging&action=login");
            htmlDoc = new HtmlDocument();
        }

2：具體方法

   /// <summary>
        /// 獲取導航
        /// </summary>
        /// <param name="fid"></param>
        /// <returns></returns>
        private string GetNav(int fid = 72)
        {
            return $"forum.php?mod=forumdisplay&fid={fid}";
        }
        /// <summary>
        /// 百度ai token
        /// </summary>
        /// <returns></returns>
        private async Task<BaiDuToken> BaiDuTokenAsync() =>
            await httpClient.GetAccessTokenAsync(); //百度ai 代碼 自我實現

        /// <summary>
        /// 搜索字符
        /// </summary>
        /// <param name="allStr"></param>
        /// <param name="firstStr"></param>
        /// <param name="lastStr"></param>
        /// <returns></returns>
        public string GetStringMid(string allStr, string firstStr, string lastStr)
        {
            int num = allStr.IndexOf(firstStr);
            int num2 = allStr.IndexOf(lastStr, num + firstStr.Length);
            if (num < 0 || num2 < 0)
            {
                return "";
            }
            num += firstStr.Length;
            num2 -= num;
            if (num < 0 || num2 < 0)
            {
                return "";
            }
            return allStr.Substring(num, num2);
        }
        /// <summary>
        /// 搜索字符
        /// </summary>
        /// <param name="allStr"></param>
        /// <param name="firstStr"></param>
        /// <param name="lastStr"></param>
        /// <param name="regexCode"></param>
        /// <returns></returns>
        public List<string> GetStringMids(string allStr, string firstStr,
            string lastStr, string regexCode = "(.*?)")
        {
            List<string> list = new List<string>();
            string pattern = $"{firstStr}{regexCode}{lastStr}";
            Regex regex = new Regex(pattern);
            MatchCollection matchCollection = regex.Matches(allStr);
            for (int i = 0; i < matchCollection.Count; i++)
            {
                GroupCollection groups = matchCollection[i].Groups;
                for (int j = 1; j < groups.Count; j++)
                {
                    string value = groups[j].Value;
                    if (!string.IsNullOrEmpty(value))
                    {
                        list.Add(value);
                    }
                }
            }
            return list;
        }
        /// <summary>
        /// 響應html為字符串
        /// </summary>
        /// <param name="url"></param>
        /// <returns></returns>
        private async Task<string> GetResponseStrAsync(string url)
        {
            return await (await GetResponseAsync(url))?.ReadAsStringAsync();
        }
        /// <summary>
        /// 響應
        /// </summary>
        /// <param name="url"></param>
        /// <returns></returns>
        private async Task<HttpContent> GetResponseAsync(string url)
        {

            HttpResponseMessage response = await httpClient.GetAsync(url);
            if (!response.IsSuccessStatusCode)
            {
                return null;
            }
            return response.Content;//具體結果
        }
        private string seccode, loginhash, formhash;
        /// <summary>
        /// 獲取登錄相關參數
        /// </summary>
        /// <returns></returns>
        private async Task GetformAsync() //獲取登錄相關參數
        {
            string url = "member.php?mod=logging&action=login";
            string html = await GetResponseStrAsync(url);
            seccode = GetStringMid(html, "seccode_", "\"");
            loginhash = GetStringMid(html, "loginhash=", "\"");
            formhash = GetStringMid(html, "<input type=\"hidden\" name=\"formhash\" value=\"", "\"");
        }
        /// <summary>
        /// 獲取驗證碼地址
        /// </summary>
        /// <returns></returns>
        private async Task<string> GetupdateAsync()//獲取驗證碼地址
        {
            string url = $"misc.php?mod=seccode&action=update&idhash={seccode}";//請求地址
            string res = await GetResponseStrAsync(url);
            return GetStringMid(res, "width=\"100\" height=\"30\" src=\"", "\"");
        }

        private async void PictureBox1_Click(object sender, EventArgs e)
        {
            await GetImageAsync();

        }

        private async void Form1_Load(object sender, EventArgs e)
        {
            await GetformAsync();
            await GetImageAsync();
            baiDuToken = await BaiDuTokenAsync();
        }

        /// <summary>
        /// 獲取驗證碼圖片
        /// </summary>
        /// <param name="update"></param>
        /// <returns></returns>
        private async Task<byte[]> GetImageAsync()
        {
            string update = await GetupdateAsync();
            byte[] bytes = await httpClient.GetByteArrayAsync(update);
            return bytes;
        }
        /// <summary>
        /// 登錄
        /// </summary>
        /// <returns></returns>
        private async Task<bool> GetLoginAsync()
        {
            byte[] bytes = await GetImageAsync();
            ImagToWords imagToWords = BaiDuAccessToken.RecogniseImage(bytes, baiDuToken);//利用百度 ai識別驗證碼
            string code = string.Join("", imagToWords.Words_result.Select(s => s.Words));
            string url = $"misc.php?mod=seccode&action=check&inajax=1&modid=member::logging&idhash={seccode}&secverify={code}";//請求地址
            string html = await GetResponseStrAsync(url);
            if (html.Contains("succeed"))
            {
                url = $"member.php?mod=logging&action=login&loginsubmit=yes&loginhash{loginhash}&inajax=1";//請求地址
                List<KeyValuePair<string, string>> paraList = new List<KeyValuePair<string, string>>
            {
                new KeyValuePair<string, string>("formhash", formhash),
                new KeyValuePair<string, string>("username", userName),
                new KeyValuePair<string, string>("password", passWord),
                new KeyValuePair<string, string>("seccodehash", seccode),
                new KeyValuePair<string, string>("seccodeverify", code),

            };
                HttpResponseMessage response = await httpClient.PostAsync(url,
                    new FormUrlEncodedContent(paraList));
                html = await response.Content.ReadAsStringAsync();
                return html.Contains("歡迎您回來");
            }
            return false;
        }

HttpClient 應用案例揭破應用Discuss論壇登錄