Send . txt file from one pc to another using http service

Question

I need to send a file from one PC to another over the network, only using requests http, so I don’t have to lower the level of socket, that takes work. Someone enables me to clear up with some API or code example?

PS: I’m not lazy, I even found a few things, only I had to make a mini server and I’m kind of layabout it.
Ah, I’m using Java and/or Python.

Answer 1

Receiving an HTTP file as a web request without using a framework is not so trivial:

To ensure the passage of the file data, along with other possible form data, and other things that go in an HTTP post, the thing is very boring.

I made a program in Python 3- without using a framework, just using the http.server module to receive a file - it works, but starts "in the box" the file data from inside the HTTP post, without parsing correctly. Surely there are dozens of corner-cases that are not treated (it is not that they are not treated properly - they are simply not treated). In particular the post data is read as "bytes" and does not have available the cool Python methods of searching and cutting strings. In particular I do a necessary gambiarra: a transparent conversion of these "bytes" to string with the "latin1" codec - this preserves the numeric value of each byte, as a Unicode character of equivalent value in the string - and in the string object, I can use split, find, Slices, etc...

On the other hand, I think it’s a nice example of how to use Python 3’s "http.server" (Basehttpserver module) in Python2.

# coding: utf-8
from http.server import HTTPServer, BaseHTTPRequestHandler
import cgi

UPLOAD_DIR = "/tmp/"

class FileSaver(BaseHTTPRequestHandler):
    def _headers(self):
        self.send_response(200)
        self.send_header("Content-type", "text/html;charset=utf-8")
        self.end_headers()

    def do_POST(self):
        files = []
        try: 
            raw_file_content = self.rfile.read(int( self.headers.get('content-length')))
            data = raw_file_content.decode("latin1")
            while True:
                try:
                    header, data = data.split("\r\n\r\n", 1)
                except ValueError:
                    break
                boundary_str = header.split("\r\n", 1)[0]
                if "filename" in header:
                    file_data = data.split("\r\n" + boundary_str)[0].encode("latin1")
                    filename = header.split('filename="')[1].split('"')[0]

                    with open(UPLOAD_DIR + filename, "wb") as file_:
                        file_.write(file_data)
                    files.append(filename)
                data = data[data.find(boundary_str):]
                if len(data) < 2:
                    break
        except Exception as exc:
            self.send_response(500)
            self.send_header("Content-type", "text/plain;charset=utf-8")
            self.end_headers()
            self.wfile.write(str(exc).encode("utf-8"))
            raise
        self._headers()
        self.wfile.write("""<h1 style="color:red">upload of {} ok</h1>""".format(filename).encode("utf-8"))
        return

    def do_GET(self):
        self._headers()

        self.wfile.write("""<h1 style="color:red">Alô mundo!!</h1>
            <form method="post" action="/" enctype="multipart/form-data">
            arquivo: <input type="file" name="arquivo"><br/>
            <input type="submit" value="ok" / >
            </form>

            """.encode("utf-8"))
        return


if __name__ == "__main__":
    server = HTTPServer(("0.0.0.0", 8000), FileSaver)
    server.serve_forever()

Of course using a framework like Flask, it’s well easier to do that. A view that saves a file that came to a forum in Flask using the WTF form extension (with the framework already taking care of all the cornercases above) would be something like:

from flask import Flask, render_template
import flask_wtf

app = Flask(__name__)

class FileForm(form):
     file = flask_wtf.file.FileField

@route("/upload", methods=["POST"])
def upload(form, id):
    form.file.data.save("/tmp/" + form.file.data.filename)
    return render_template(...)

(This code in Flask is not complete and has not been tested - the above raw Pythno works as is)

Already the code to post a file by HTTP - again, if using Python "raw" can be quite complicated - but in this case, we can use the method "requests" that accepts a parameter "file" directly (it receives a dictionary with the name of the file field and an open file, which we wish to send):

>>> requests.post("http://localhost:8000", files={"arquivo": open("imagem.png", "rb")  } )

Only this call uploads the file to the list 1 server above.

Now, it’s one thing to want to play with it, it’s another to want to use it in production - in this case it’s better to either use the framework, of course, or use xmlrpc (or jsonrpc) - it’s going to be an easier order of magnitude.