Send a PUT request with a file and custom headers - http

Question

I am stuck at a problem.
I need to upload a file (a CSV file) to a server by using Delphi. The server have certain requirements that must be followed :
The request must be an HTTP PUT request.
Must contain the Client ID in the URL request, like this : example.com/upload/{Client ID} ({Client ID} would be replaced).
Must contain the future file name that will be received also in the URL after the client ID, like this : example.com/upload/{Client ID}/{Future File Name} ({Future File Name} would be replaced), which can be different from your local file name.
The API Key must be in the request header (header name: x-api-key). Example : lXViWTzFic9sM8qe9Ew7JME8xTdBAOMJHdIjK7XkjQ00OWr.
I could do this in CURL, like this example : (Client ID : d32krpq, and Future file name : 20181023_update.csv)
curl -v -X PUT https://example.com/upload/d32krpq/20181023_update.csv --upload-file 20181023_update.csv --header "x-api-key: lXViWTzFic9sM8qe9Ew7JME8xTdBAOMJHdIjK7XkjQ00OWr"
How to achieve this using Delphi components (using either TNetHttpClient or TRESTClient)?

Answer 1

In Delphi, sending multiple fields (files, custom headers, body fields, ...) in your PUT request is possible in both HTTP client frameworks:
In TNetHTTPClient through the method Put(), you can use the overloaded function with the local file path's string parameter. And in the function's optional parameter of TNetHeaders object, you specify your custom header parameters.
TNetHeaders is a dynamic array of the TNameValuePair record.
So, you have to create a dynamic array of TNameValuePair, then you create an instance of the TNameValuePair record with your API key and add it to the dynamic array.
With the exception that in TNetHTTPClient, you have to specify the URL segments parameter directly in your URL's request by yourself.
And finally, you call the Put() method with your file path's string and TNetHeaders objects, like this example:
procedure TForm1.PutFile;
var
LHTTP: TNetHTTPClient;
LHeaders: array of TNameValuePair;
begin
SetLength(LHeaders, 1);
LHeaders[0] := TNameValuePair.Create('x-api-key', 'lXViWTzFic9sM8qe9Ew7JME8xTdBAOMJHdIjK7XkjQ00OWr');
LHTTP := TNetHTTPClient.Create(nil);
try
LHTTP.Put('https://example.com/upload/d32krpq/20181023_update.csv', 'C:/MyFile.csv', nil, LHeaders);
finally
LHTTP.Free;
end;
end;
For the REST Client library, you can simply use the TRESTRequest.AddFile() function to add a file, and you can use the AddParameter() function to add any custom fields as a body, an URL segment or a header parameter.
Another advantage in TRESTClient is that you can use a base URL or a resource where you define URL segments, like "example.com/upload/{Client ID}/{Future File Name}".
Drop the components TRESTClient, TRESTRequest, and TRESTResponse on the form, set the TRESTClient.BaseURL to your upload server, and write your code. Like in this example:
procedure TForm1.PutFile;
begin
try
try
RESTRequest1.Method := TRESTRequestMethod.rmPUT;
RESTRequest1.AddFile('File1', 'C:\MyFile.csv', TRESTContentType.ctTEXT_CSV);
// Adding the parameters to be included in the URL
RESTRequest1.AddField('Client ID', 'd32krpq', pkURLSEGMENT);
RESTRequest1.AddField('Future File Name', '20181023_update.csv', pkURLSEGMENT);
// Adding a header parameter
RESTRequest1.AddField('x-api-key', 'lXViWTzFic9sM8qe9Ew7JME8xTdBAOMJHdIjK7XkjQ00OWr', pkHTTPHeader);
RESTRequest1.Execute;
except
ShowMessage('Uploading failed');
end;
finally
ShowMessage(RESTRequest1.Response.Content); // here you can see your server's response
end;
end;

Answer 2

Here is an alternative approach using Indy's TIdHTTP component:
FS := TIdReadFileExclusiveStream.Create('20181023_update.csv');
try
IdHTTP1.Request.CustomHeaders.Values['x-api-key'] := 'lXViWTzFic9sM8qe9Ew7JME8xTdBAOMJHdIjK7XkjQ00OWr';
IdHTTP1.Put('https://example.com/upload/d32krpq/20181023_update.csv', FS);
finally
FS.Free;
end;