Replace form_type and header_type with pair_type derived type (#34)

* Replace form_type and header_type with pair_type derived type

* Add functionality for sending files via HTTP POST requests.

* Refactor the set_body procedure

* add HTTP_PUT

* Edit docstrings

* Indentation

* Move data/file.txt in example/

---------

Co-authored-by: milancurcic <caomaco@gmail.com>

Author: rajkumardongre

example/data/file.txt

@@ -0,0 +1 @@
+Here is the data from the file that needs to be sent to the server.

example/post.f90

@@ -1,13 +1,14 @@
 program post_request
     ! This program demonstrates sending JSON data using POST request and printing the
     ! status, length of the body, method, and the body of the response.
-    use http, only: response_type, request, HTTP_POST, header_type
+    use http, only: response_type, request, HTTP_POST, pair_type
     implicit none
     type(response_type) :: response
     character(:), allocatable :: json_data
-    type(header_type), allocatable :: req_header(:)
+    type(pair_type), allocatable :: req_header(:)
 
-    req_header = [header_type('Content-Type', 'application/json')]
+    ! Storing request header in array of pair_type object
+    req_header = [pair_type('Content-Type', 'application/json')]
 
     ! JSON data we want to send
     json_data = '{"name":"Jhon","role":"developer"}'

example/post_file.f90

@@ -0,0 +1,23 @@
+program post_file
+
+    ! This program demonstrates sending File using POST request.
+    
+    use http, only : request, response_type, HTTP_POST, pair_type
+    implicit none
+    type(response_type) :: response
+    type(pair_type) :: file_data
+
+    ! pair_type('<file_field_name>', '/path/to/file.txt')
+    file_data = pair_type('file.txt', './example/data/file.txt')
+
+    response = request(url='https://httpbin.org/post', method=HTTP_POST, file=file_data)
+
+    if(.not. response%ok) then
+        print *,'Error message : ', response%err_msg
+    else
+        print *, 'Response Code    : ', response%status_code
+        print *, 'Response Length  : ', response%content_length
+        print *, 'Response Method  : ', response%method
+        print *, 'Response Content : ', response%content
+    end if
+end program post_file

example/post_form_data.f90

@@ -1,13 +1,15 @@
 program post_form_data
-    ! This program demonstrates sending Form data using POST request and printing the
-    ! status, length of the body, method, and the body of the response.
-    use http, only: response_type, request, HTTP_POST, header_type, form_type
+    ! This program demonstrates sending Form data using POST request and printing 
+    ! the status, length of the body, method, and the body of the response.
+    use http, only: response_type, request, HTTP_POST, pair_type
     implicit none
     type(response_type) :: response
-    type(header_type), allocatable :: req_header(:)
-    type(form_type), allocatable :: form_data(:)
+    type(pair_type), allocatable :: req_header(:)
+    type(pair_type), allocatable :: form_data(:)
 
-    form_data = [form_type('param1', 'value1'), form_type('param2', 'value2')]
+    ! Storing form data in a array of pair_type object, each pair_type object 
+    ! represent a single form field
+    form_data = [pair_type('param1', 'value1'), pair_type('param2', 'value2')]
 
     response = request(url='https://httpbin.org/post', method=HTTP_POST, form=form_data)
 

example/response_header.f90

@@ -2,20 +2,22 @@ program response_header
     ! This program demonstrates sending user-provided headers in a GET request
     ! and iterating over the headers of the response sent back by the server.
     use stdlib_string_type, only: string_type, write(formatted)
-    use http, only: response_type, request, header_type
+    use http, only: response_type, request, pair_type
 
     implicit none
     type(response_type) :: response
-    type(header_type), allocatable :: header(:), req_header(:)
+    type(pair_type), allocatable :: header(:), req_header(:)
     character(:), allocatable :: val
     integer :: i = 0
 
+    ! Storing request header in array of pair_type object, where each pair_type
+    ! object represents a single header. (in header-name,header-value format)
     req_header = [ &
-      header_type('Another-One', 'Hello'), &
-      header_type('Set-Cookie', 'Theme-Light'), &
-      header_type('Set-Cookie', 'Auth-Token: 12345'), &
-      header_type('User-Agent', 'my user agent') &
-      ]
+      pair_type('Another-One', 'Hello'), &
+      pair_type('Set-Cookie', 'Theme-Light'), &
+      pair_type('Set-Cookie', 'Auth-Token: 12345'), &
+      pair_type('User-Agent', 'my user agent') &
+    ]
 
     response = request(url='https://httpbin.org/get', header=req_header)
 
@@ -28,7 +30,7 @@ program response_header
         header = response%header
         ! Iterate over response headers.
         do i = 1, size(header)
-            print *, header(i)%key, ': ', header(i)%value
+            print *, header(i)%name, ': ', header(i)%value
         end do
 
         ! getting header value by header name

src/http.f90

@@ -1,8 +1,7 @@
 module http
     use http_request, only: &
-        HTTP_DELETE, HTTP_GET, HTTP_HEAD, HTTP_PATCH, HTTP_POST, HTTP_POST
+        HTTP_DELETE, HTTP_GET, HTTP_HEAD, HTTP_PATCH, HTTP_POST, HTTP_PUT
     use http_response, only: response_type
     use http_client, only: request
-    use http_header, only : header_type
-    use http_form, only : form_type
+    use http_pair, only : pair_type
 end module http