Http Client in Co-array Fortran

Here’s the translation of the HTTP Client example from Go to Co-array Fortran, formatted in Markdown suitable for Hugo:

program http_client
  use iso_fortran_env
  use http_module
  implicit none

  type(http_response) :: resp
  integer :: status
  character(len=1024) :: line
  integer :: i

  ! Issue an HTTP GET request to a server
  resp = http_get("https://example.com")
  if (resp%status /= 0) then
    error stop "Failed to make HTTP request"
  end if

  ! Print the HTTP response status
  print *, "Response status: ", resp%status_code

  ! Print the first 5 lines of the response body
  do i = 1, 5
    call readline(resp%body, line, status)
    if (status /= 0) exit
    print *, trim(line)
  end do

  ! Clean up
  call http_response_free(resp)

end program http_client

This Co-array Fortran program demonstrates how to make a simple HTTP GET request and process the response. Here’s a breakdown of what the code does:

1. We use a hypothetical http_module that provides HTTP client functionality. This module would need to be implemented or obtained from a third-party library, as Fortran doesn’t have built-in HTTP support.

2. We define an http_response type to hold the response from the server.

3. The http_get function is used to make a GET request to “https://example.com”. In a real implementation, this function would handle the network communication and return the response.

4. We check the status of the response. If it’s not successful, we stop the program with an error message.

5. We print the HTTP response status code.

6. We then print the first 5 lines of the response body. The readline subroutine is used to read lines from the response body.

7. Finally, we clean up by freeing the response object.

To run this program, you would need to compile it with a Fortran compiler that supports Co-array Fortran, and link it with the necessary HTTP client library. The exact command would depend on your specific environment and the HTTP library you’re using.

Note that Co-array Fortran is primarily designed for parallel programming, and doesn’t have built-in support for HTTP operations. In a real-world scenario, you might need to use a separate library or interface with C code to perform HTTP requests. The example above is a simplified representation to demonstrate the concept.