Support `-F` / `--form` in the Multipart parameters

[dariusz-wozniak]

I'd like to create a ticket with attachment in the Freshdesk API [API reference].

Example of the cURL for the request:

curl -v -u yourapikey:X -F "attachments[]=@/path/to/attachment1.ext" -F "attachments[]=@/path/to/attachment2.ext" -F "email=example@example.com" -F "subject=Ticket Title" -F "description=this is a sample ticket" -X POST 'https://domain.freshdesk.com/api/v2/tickets'

When the following RestSharp code is used:

var request = new RestRequest("tickets", Method.Post);
request.AlwaysMultipartFormData = true;

request.AddParameter("email", ticket.Email);
request.AddParameter("description", ticket.Description);
request.AddParameter("subject", ticket.Subject);
request.AddParameter("status", ticket.Status);
request.AddParameter("priority", ticket.Priority);

var rs = await client.ExecuteAsync(request);

...Then it results with the 400 BadRequest with the following response:

{
    "description": "Validation failed",
    "errors": [
        {
            "code": "invalid_field",
            "field": "email\r\n",
            "message": "Unexpected/invalid field in request"
        },
        {
            "code": "invalid_field",
            "field": "subject\r\n",
            "message": "Unexpected/invalid field in request"
        },
        {
            "code": "invalid_field",
            "field": "status\r\n",
            "message": "Unexpected/invalid field in request"
        },
        {
            "code": "invalid_field",
            "field": "priority\r\n",
            "message": "Unexpected/invalid field in request"
        },
        {
            "code": "invalid_field",
            "field": "description\r\n",
            "message": "Unexpected/invalid field in request"
        }
    ]
}

The above works fine in Postman:

The request is to provide a proper ParameterType to handle the above scenario.

[alexeyzimarev]

Can you explain what that -F thing does? I am a bit confused as the request in Postman looks like JSON, not a form.

[dariusz-wozniak]

In the Postman, the current selection is a form-data.

There's also a Code snippet view; for RestSharp the generated code (that doesn't work) is as the following (sensitive data removed):

var client = new RestClient("https://SENSITIVE.freshdesk.com/api/v2/tickets");
client.Timeout = -1;
var request = new RestRequest(Method.POST);
request.AddHeader("Content-Type", "multipart/form-data");
request.AddHeader("Authorization", "Basic SENSITIVE");
request.AddHeader("Cookie", "_x_w=5_2");
request.AlwaysMultipartFormData = true;
request.AddParameter("email", "a@a.com");
request.AddParameter("subject", "Test ticket");
request.AddParameter("description", "Test ticket");
request.AddParameter("status", "2");
request.AddParameter("priority", "1");
IRestResponse response = client.Execute(request);
Console.WriteLine(response.Content);

On the -F (source: https://curl.se/docs/manpage.html#-F):

-F, --form <name=content>

(HTTP SMTP IMAP) For HTTP protocol family, this lets curl emulate a filled-in form in which a user has pressed the submit button. This causes curl to POST data using the Content-Type multipart/form-data according to RFC 2388.

For SMTP and IMAP protocols, this is the means to compose a multipart mail message to transmit.

This enables uploading of binary files etc. To force the 'content' part to be a file, prefix the file name with an @ sign. To just get the content part from a file, prefix the file name with the symbol <. The difference between @ and < is then that @ makes a file get attached in the post as a file upload, while the < makes a text field and just get the contents for that text field from a file.

Tell curl to read content from stdin instead of a file by using - as filename. This goes for both @ and < constructs. When stdin is used, the contents is buffered in memory first by curl to determine its size and allow a possible resend. Defining a part's data from a named non-regular file (such as a named pipe or similar) is unfortunately not subject to buffering and will be effectively read at transmission time; since the full size is unknown before the transfer starts, such data is sent as chunks by HTTP and rejected by IMAP.

Example: send an image to an HTTP server, where 'profile' is the name of the form-field to which the file portrait.jpg will be the input:

curl -F profile=@portrait.jpg https://example.com/upload.cgi

[alexeyzimarev]

Here's what I did:

var ticket = new {
    Email       = "test@acme.org",
    Description = "description",
    Subject     = "subject",
    Status      = "status",
    Priority    = "low"
};
var client = new RestClient("https://enqvvdg27q3o.x.pipedream.net/");

var request = new RestRequest("tickets", Method.Post)
    .AddFile("test.cs", "test.txt")
    .AddParameter("email", ticket.Email)
    .AddParameter("description", ticket.Description)
    .AddParameter("subject", ticket.Subject)
    .AddParameter("status", ticket.Status)
    .AddParameter("priority", ticket.Priority);

var rs = await client.ExecuteAsync(request);

And that's how the request looks like:

It's hard for me to guess what exactly FreshDesk is unhappy about as the request looks completely legit.

[alexeyzimarev]

I know what is the issue with FreshDesk API and it has nothing to do with supporting multipart form data parameters as they are supported for many years.