Remove requests dependency

Use urllib.request to replace requests.
Users no longer need to install an extra Python package to get it run.

README.md

@@ -4,7 +4,7 @@ A script for speed testing for each mirrors providing mirrorz service.
 
 ## How to use
 
-Make sure you have `curl` installed. Also at least Python 3.5 is required, and `requests` package is installed.
+Make sure you have `curl` installed. Also at least Python 3.5 is required.
 
 Use
 
@@ -24,8 +24,8 @@ If you get stuck when loading meta data, you may issue `Ctrl+C` to skip one mirr
 
 ## Proxy
 
-This script sends two kinds of http request: python `requests` to get metadata and `curl` to do actual speed test.
+This script sends two kinds of http request: python `urllib.request` (built-in) to get metadata and `curl` to do actual speed test.
 
-Some sites provide their meta data (`mirrorz.json`) in a place that is hard to access, which you may use a proxy. In this case you may set `HTTP_PROXY` or `HTTPS_PROXY`, which is used by python `requests`.
+Some sites provide their meta data (`mirrorz.json`) in a place that is hard to access, which you may use a proxy. In this case you may set `HTTP_PROXY` or `HTTPS_PROXY`, which is used by python `urllib.request`.
 
-In some settings you may use a proxy to do actual downloading, in this case you may set `http_proxy` or `https_proxy`. Note that these lowercase envs are also read by python `requests`.
+In some settings you may use a proxy to do actual downloading, in this case you may set `http_proxy` or `https_proxy`. Note that these lowercase envs are also read by python `urllib.request`.

oh-my-mirrorz.py

@@ -3,8 +3,8 @@
 # vim: expandtab ts=4 sts=4 sw=4
 
 import subprocess
-import requests
-import sys
+import urllib.request
+import json
 import os
 import argparse
 
@@ -45,10 +45,14 @@ def check_curl():
         return -1
 
 def site_info(url):
-    return requests.get(url,
-                        headers={
-                            'User-Agent': 'oh-my-mirrorz/%s (+https://github.com/mirrorz-org/oh-my-mirrorz) %s %s' % (VERSION, UA_URL, requests.utils.default_user_agent())
-                        }, timeout=10).json()
+    user_agent = 'oh-my-mirrorz/%s (+https://github.com/mirrorz-org/oh-my-mirrorz) %s %s' % (VERSION, UA_URL, "urllib/" + urllib.request.__version__)
+    headers = {
+        'User-Agent': user_agent
+    }
+
+    request = urllib.request.Request(url, headers=headers)
+    with urllib.request.urlopen(request, timeout=10) as response:
+        return json.loads(response.read().decode('utf-8'))
 
 
 def speed_test(url, args):