如何通过Adobe Sign API上传已有带标签表单并发起签署（C#/.NET7）

核心问题说明 #

你当前的代码调用的是Adobe PDF Services API的DocumentMergeOperation，这是用于从模板生成新文档的服务，和你需要的Adobe Sign API是两个独立的服务，这也是代码无法满足需求的根本原因。

正确操作流程 #

要使用已有带标签的PDF表单发起签署，流程分为两步：

• 第一步：将现有PDF上传到Adobe Sign，获取文档ID（可选择Transient Documents临时存储，有效期7天；或Library Documents永久存储）
• 第二步：使用该文档ID创建签署协议（Agreement），指定签署人、签署顺序等信息

修复Transient Document上传无响应问题 #

你之前调用Transient Document API无结果，大概率是请求认证或参数不正确。以下是.NET7中使用HttpClient的正确实现：

using System.Net.Http.Headers;
using System.Text;

var clientId = Environment.GetEnvironmentVariable("ADOBE_SIGN_CLIENT_ID");
var clientSecret = Environment.GetEnvironmentVariable("ADOBE_SIGN_CLIENT_SECRET");

// 1. 获取Adobe Sign访问令牌
var tokenResponse = await GetAdobeSignAccessToken(clientId, clientSecret);
var accessToken = tokenResponse.access_token;

// 2. 上传带标签的PDF到Transient Documents
var pdfPath = @"C:\Test\Your-Tagged-Form.pdf";
var transientDocId = await UploadTransientDocument(accessToken, pdfPath);

Console.WriteLine($"Transient Document ID: {transientDocId}");

// 获取AccessToken的方法
async Task<dynamic> GetAdobeSignAccessToken(string clientId, string clientSecret)
{
    using var client = new HttpClient();
    var authString = Convert.ToBase64String(Encoding.ASCII.GetBytes($"{clientId}:{clientSecret}"));
    client.DefaultRequestHeaders.Authorization = new AuthenticationHeaderValue("Basic", authString);

    var formData = new Dictionary<string, string>
    {
        {"grant_type", "client_credentials"},
        {"scope", "user_login:self"}
    };

    var response = await client.PostAsync("https://api.na1.adobe.com/oauth/token", new FormUrlEncodedContent(formData));
    response.EnsureSuccessStatusCode();
    return await response.Content.ReadFromJsonAsync<dynamic>();
}

// 上传Transient Document的方法
async Task<string> UploadTransientDocument(string accessToken, string filePath)
{
    using var client = new HttpClient();
    client.DefaultRequestHeaders.Authorization = new AuthenticationHeaderValue("Bearer", accessToken);

    using var content = new MultipartFormDataContent();
    var fileContent = new ByteArrayContent(File.ReadAllBytes(filePath));
    fileContent.Headers.ContentType = MediaTypeHeaderValue.Parse("application/pdf");
    content.Add(fileContent, "File", Path.GetFileName(filePath));

    var response = await client.PostAsync("https://api.na1.adobe.com/restapi/v6/transientDocuments", content);
    response.EnsureSuccessStatusCode();
    var result = await response.Content.ReadFromJsonAsync<dynamic>();
    return result.transientDocumentId;
}

创建签署协议 #

拿到transientDocId后，即可发起签署请求：

async Task<string> CreateSigningAgreement(string accessToken, string transientDocId)
{
    using var client = new HttpClient();
    client.DefaultRequestHeaders.Authorization = new AuthenticationHeaderValue("Bearer", accessToken);
    client.DefaultRequestHeaders.Accept.Add(new MediaTypeWithQualityHeaderValue("application/json"));

    var agreementPayload = new
    {
        name = "ACH Form Signing Request",
        participantSetsInfo = new[]
        {
            new
            {
                memberInfos = new[]
                {
                    new { email = "signer@example.com" }
                },
                order = 1,
                role = "SIGNER"
            }
        },
        documentInfos = new[]
        {
            new { transientDocumentId = transientDocId }
        },
        signatureType = "ESIGN",
        state = "IN_PROCESS"
    };

    var jsonPayload = JsonContent.Create(agreementPayload);
    var response = await client.PostAsync("https://api.na1.adobe.com/restapi/v6/agreements", jsonPayload);
    response.EnsureSuccessStatusCode();
    var result = await response.Content.ReadFromJsonAsync<dynamic>();
    return result.id;
}

关键注意事项 #

• 确保你的Adobe Sign应用已启用权限：需包含agreements:write、transientDocuments:write等权限
• 调整API端点：na1为北美环境，根据你的账号区域替换为eu1（欧洲）、ap1（亚太）等
• 带标签的PDF无需额外处理，Adobe Sign会自动识别表单域
• 若需重复使用表单，可上传为Library Document（永久存储），对应API端点为/restapi/v6/libraryDocuments

内容的提问来源于stack exchange，提问作者I.M.Groot