鉴于以下尝试将数据发布到生成PDF文件的Web服务， PDF火箭 （顺便说一下这真棒）。
我收到了错误 无效的URI：uri字符串太长
为什么有人会施加任意限制 POSTed数据？
using (var client = new HttpClient())
{
// Build the conversion options
var options = new Dictionary<string, string>
{
{ "value", html },
{ "apikey", ConfigurationManager.AppSettings["pdf:key"] },
{ "MarginLeft", "10" },
{ "MarginRight", "10" }
};
// THIS LINE RAISES THE EXCEPTION
var content = new FormUrlEncodedContent(options);
var response = await client.PostAsync("https://api.html2pdfrocket.com/pdf", content);
var result = await response.Content.ReadAsByteArrayAsync();
return result;
}
我收到这个荒谬的错误。
{System.UriFormatException: Invalid URI: The Uri string is too long.
at System.UriHelper.EscapeString
at System.Uri.EscapeDataString
at System.Net.Http.FormUrlEncodedContent.Encode
at System.Net.Http.FormUrlEncodedContent.GetContentByteArray
这让我想起了 640k 应该够了......我的意思是 真？
使用帖子可以包含http消息中的内容而不是URI。 uri的最大长度为2083个字符。您可以在http消息中将其作为JSON发送而不是URI，这是在HttpPost / HttpPut中发送更大块数据的推荐方法。我改变了你的代码来使用它。这假设您正在联系的服务可以使用JSON（.net Web Api开箱即用应该没有问题）。
using (var client = new HttpClient())
{
// Build the conversion options
var options = new
{
value = html,
apikey = ConfigurationManager.AppSettings["pdf:key"],
MarginLeft = "10",
MarginRight = "10"
};
// Serialize our concrete class into a JSON String
var stringPayload = JsonConvert.SerializeObject(options);
var content = new StringContent(stringPayload, Encoding.UTF8, "application/json");
var response = await client.PostAsync("https://api.html2pdfrocket.com/pdf", content);
var result = await response.Content.ReadAsByteArrayAsync();
return result;
}
一定要安装 newtonsoft json。
我刚刚解决了类似的问题。对我来说，我正在与我无法控制的后端集成，并且必须将POST文件与表单数据（例如customerID）一起作为表单变量。因此切换到JSON或Multipart会破坏我无法控制的后端。问题是大文件会导致FormUrlEncodedContent抛出错误，说“uri字符串太长”。
这是经过两天努力后为我解决的代码（注意仍然需要调整为ASYNC）。
private string UploadFile(string filename, int CustomerID, byte[] ImageData) {
string Base64String = "data:image/jpeg;base64," + Convert.ToBase64String(ImageData, 0, ImageData.Length);
var baseAddress = new Uri("[PUT URL HERE]");
var cookieContainer = new CookieContainer();
using (var handler = new HttpClientHandler() { AllowAutoRedirect = true, UseCookies = true, CookieContainer = cookieContainer })
using (var client = new HttpClient(handler) { BaseAddress = baseAddress })
{
try {
//ENCODE THE FORM VARIABLES DIRECTLY INTO A STRING rather than using a FormUrlEncodedContent type which has a limit on its size.
string FormStuff = string.Format("name={0}&file={1}&id={2}", filename, HttpUtility.UrlEncode(Base64String), CustomerID.ToString());
//THEN USE THIS STRING TO CREATE A NEW STRINGCONTENT WHICH TAKES A PARAMETER WHICH WILL FormURLEncode IT AND DOES NOT SEEM TO THROW THE SIZE ERROR
StringContent content = new StringContent(FormStuff, Encoding.UTF8, "application/x-www-form-urlencoded");
//UPLOAD
string url = string.Format("/ajax/customer_image_upload.php");
response = client.PostAsync(url, content).Result;
return response.Content.ToString();
}
catch (Exception ex) {
return ex.ToString();
}
}
}
如果像我一样，你面对的是一些只接受表单内容的第三方网络服务，你可以解决这个问题：
// Let's assume you've got your key-value pairs organised into a nice Dictionary<string, string> called formData
var encodedItems = formData.Select(i => WebUtility.UrlEncode(i.Key) + "=" + WebUtility.UrlEncode(i.Value));
var encodedContent = new StringContent(String.Join("&", encodedItems), null, "application/x-www-form-urlencoded");
// Post away!
var response = await client.PostAsync(url, encodedContent);