C HttpClient 4 5 multipart form-data upload

Question

Does anyone know how to use the HttpClient in  Net 4 5 with multipart form-data upload    I couldn t find any examples on the internet

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Here s a complete sample that worked for me  The boundary value in the request is added automatically by  NET   var url    http   localhost api v1 yourendpointhere   var filePath     C  path to image jpg    HttpClient httpClient   new HttpClient    MultipartFormDataContent form   new MultipartFormDataContent     FileStream fs   File OpenRead filePath   var streamContent   new StreamContent fs    var imageContent   new ByteArrayContent streamContent ReadAsByteArrayAsync   Result   imageContent Headers ContentType   MediaTypeHeaderValue Parse  multipart form-data     form Add imageContent   image   Path GetFileName filePath    var response   httpClient PostAsync url  form  Result

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X509Certificate clientKey1   null  clientKey1   new X509Certificate AppSetting  certificatePath    AppSetting  pswd     string url    https   EndPointAddress   FileStream fs   File OpenRead FilePath   var streamContent   new StreamContent fs    var FileContent   new ByteArrayContent streamContent ReadAsByteArrayAsync   Result   FileContent Headers ContentType   MediaTypeHeaderValue Parse  ContentType    var handler   new WebRequestHandler      handler ClientCertificateOptions   ClientCertificateOption Manual  handler ClientCertificates Add clientKey1   handler ServerCertificateValidationCallback    httpRequestMessage  cert  cetChain  policyErrors    gt        return true       using  var client   new HttpClient handler            Post it     HttpResponseMessage httpResponseMessage   client PostAsync url  FileContent  Result       if   httpResponseMessage IsSuccessStatusCode                string ss   httpResponseMessage StatusCode ToString

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my result looks like this   public static async Task lt string gt  Upload byte   image         using  var client   new HttpClient                    using  var content                new MultipartFormDataContent  Upload----    DateTime Now ToString CultureInfo InvariantCulture                            content Add new StreamContent new MemoryStream image     bilddatei    upload jpg                   using                    var message                        await client PostAsync  http   www directupload net index php mode upload   content                                     var input   await message Content ReadAsStringAsync                       return  string IsNullOrWhiteSpace input    Regex Match input    http    w   directupload  net images  d   w    a-z  3    Value   null

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Example with preloader Dotnet 3 0 Core  ProgressMessageHandler processMessageHander   new ProgressMessageHandler     processMessageHander HttpSendProgress     s  e    gt        if  e ProgressPercentage  gt  0                ProgressPercentage   e ProgressPercentage          TotalBytes   e TotalBytes          progressAction  Invoke progressFile             using  var client   HttpClientFactory Create processMessageHander         var uri   new Uri transfer BackEndUrl       client DefaultRequestHeaders Authorization       new AuthenticationHeaderValue  Bearer   AccessToken        using  MultipartFormDataContent multiForm   new MultipartFormDataContent                  multiForm Add new StringContent FileId    FileId            multiForm Add new StringContent FileName    FileName            string hash                using  MD5 md5Hash   MD5 Create                          var sb   new StringBuilder                foreach  var data in md5Hash ComputeHash File ReadAllBytes FullName                                  sb Append data ToString  x2                               hash   result ToString                      multiForm Add new StringContent hash    Hash             using  FileStream fs   File OpenRead FullName                         multiForm Add new StreamContent fs    file   Path GetFileName FullName                var response   await client PostAsync uri  multiForm               progressFile Message   response ToString                 if  response IsSuccessStatusCode                    progressAction  Invoke progressFile                 else                   progressErrorAction  Invoke progressFile                             response EnsureSuccessStatusCode

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public async Task lt object gt  PassImageWithText IFormFile files        byte   data      string result           ByteArrayContent bytes       MultipartFormDataContent multiForm   new MultipartFormDataContent         try               using  var client   new HttpClient                          using  var br   new BinaryReader files OpenReadStream                                   data   br ReadBytes  int files OpenReadStream   Length                              bytes   new ByteArrayContent data               multiForm Add bytes   files   files FileName               multiForm Add new StringContent  value1     key1                multiForm Add new StringContent  value2     key2                 var res   await client PostAsync  MEDIA ADD IMG URL  multiForm                       catch  Exception e                throw new Exception e ToString                return result

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Try this its working for me   private static async Task lt object gt  Upload string actionUrl        Image newImage   Image FromFile   Absolute Path of image        ImageConverter  imageConverter   new ImageConverter        byte   paramFileStream   byte    imageConverter ConvertTo newImage  typeof byte           var formContent   new MultipartFormDataContent                  Send form text values here          new StringContent  value1    key1             new StringContent  value2    key2                Send Image Here          new StreamContent new MemoryStream paramFileStream    imagekey   filename jpg               var myHttpClient   new HttpClient        var response   await myHttpClient PostAsync actionUrl ToString    formContent       string stringContent   await response Content ReadAsStringAsync         return response

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I m adding a code snippet which shows on how to post a file to an API which has been exposed over DELETE http verb  This is not a common case to upload a file with DELETE http verb but it is allowed  I ve assumed Windows NTLM authentication for authorizing the call   The problem that one might face is that all the overloads of HttpClient DeleteAsync method have no parameters for HttpContent the way we get it in PostAsync method  var requestUri   new Uri  http   UrlOfTheApi    using  var streamToPost   new MemoryStream  C  temp txt    using  var fileStreamContent   new StreamContent streamToPost   using  var httpClientHandler   new HttpClientHandler     UseDefaultCredentials   true    using  var httpClient   new HttpClient httpClientHandler  true   using  var requestMessage   new HttpRequestMessage HttpMethod Delete  requestUri   using  var formDataContent   new MultipartFormDataContent          formDataContent Add fileStreamContent   myFile    temp txt        requestMessage Content   formDataContent      var response   httpClient SendAsync requestMessage  GetAwaiter   GetResult         if  response IsSuccessStatusCode                   File upload was successfull           else               var erroResult   response Content ReadAsStringAsync   GetAwaiter   GetResult            throw new Exception  Error on the server       erroResult             You need below namespaces at the top of your C  file   using System  using System Net  using System IO  using System Net Http    P S  Sorry about so many using blocks IDisposable pattern  in my code  Unfortunately  the syntax of using construct of C  doesn t support initializing multiple variables in single statement

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Here is another example on how to use HttpClient to upload a multipart form-data   It uploads a file to a REST API and includes the file itself  e g  a JPG  and additional API parameters  The file is directly uploaded from local disk via FileStream   See here for the full example including additional API specific logic   public static async Task UploadFileAsync string token  string path  string channels           we need to send a request with multipart form-data     var multiForm   new MultipartFormDataContent            add API method parameters     multiForm Add new StringContent token    token        multiForm Add new StringContent channels    channels            add file and directly upload it     FileStream fs   File OpenRead path       multiForm Add new StreamContent fs    file   Path GetFileName path            send request to API     var url    https   slack com api files upload       var response   await client PostAsync url  multiForm

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It works more or less like this  example using an image jpg file    async public Task lt HttpResponseMessage gt  UploadImage string url  byte   ImageData        var requestContent   new MultipartFormDataContent               here you can specify boundary if you need---      var imageContent   new ByteArrayContent ImageData       imageContent Headers ContentType            MediaTypeHeaderValue Parse  image jpeg         requestContent Add imageContent   image    image jpg         return await client PostAsync url  requestContent        You can requestContent Add   whatever you want  take a look at the HttpContent descendant to see available types to pass in   When completed  you ll find the response content inside HttpResponseMessage Content that you can consume with HttpContent ReadAs Async

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This is an example of how to post string and file stream with HTTPClient using MultipartFormDataContent  The Content-Disposition and Content-Type need to be specified for each HTTPContent   Here s my example  Hope it helps   private static void Upload         using  var client   new HttpClient                  client DefaultRequestHeaders Add  User-Agent    CBS Brightcove API Service             using  var content   new MultipartFormDataContent                          var path     C  B2BAssetRoot files 596086 596086 1 mp4                string assetName   Path GetFileName path                var request   new HTTPBrightCoveRequest                                         Method    create video                       Parameters   new Params                                                         CreateMultipleRenditions    true                               EncodeTo   EncodeTo Mp4 ToString   ToUpper                                Token    x8sLalfXacgn-4CzhTBm7uaCxVAPjvKqTf1oXpwLVYYoCkejZUsYtg                                 Video   new Video                                                                         Name   assetName                                      ReferenceId   Guid NewGuid   ToString                                        ShortDescription   assetName                                                                                               Content-Disposition  form-data  name  json              var stringContent   new StringContent JsonConvert SerializeObject request                stringContent Headers Add  Content-Disposition    form-data  name   json                  content Add stringContent   json                 FileStream fs   File OpenRead path                var streamContent   new StreamContent fs               streamContent Headers Add  Content-Type    application octet-stream                  Content-Disposition  form-data  name  file   filename  C  B2BAssetRoot files 596090 596090 1 mp4               streamContent Headers Add  Content-Disposition    form-data  name   file    filename       Path GetFileName path                       content Add streamContent   file   Path GetFileName path                   content Headers ContentDisposition   new ContentDispositionHeaderValue  attachment                 Task lt HttpResponseMessage gt  message   client PostAsync  http   api brightcove com services post   content                var input   message Result Content ReadAsStringAsync                Console WriteLine input Result               Console Read

[c#] C# HttpClient 4.5 multipart/form-data upload

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