mpremote: Support HTTP(S) for fs cp SRC

Enables copying directly from a http/https URL.
Convenient for putting resources onto device without needing to make
a local copy or using external download tool.
Usecases include installing module that is not mpip installable,
or adding resource files such as fonts/images/blobs

Signed-off-by: Jon Nordby <jononor@gmail.com>

tools/mpremote/mpremote/transport_serial.py

@@ -35,7 +35,7 @@
 # Once the API is stabilised, the idea is that mpremote can be used both
 # as a command line tool and a library for interacting with devices.
 
-import ast, io, errno, os, re, struct, sys, time
+import ast, io, errno, os, re, struct, sys, time, contextlib, urllib
 from collections import namedtuple
 from errno import EPERM
 from .console import VT_ENABLED
@@ -58,6 +58,24 @@ def reraise_filesystem_error(e, info):
     raise
 
 
+@contextlib.contextmanager
+def open_file(src : str):
+    """Open a file. Can be either on local disk or a HTTP(S) URL"""
+    is_http = src.startswith('https://') or src.startswith('http://')
+    if is_http:
+        conn = urllib.request.urlopen(src, timeout=60.0)
+        size = int(conn.headers['content-length'])
+        file_like = conn
+    else:
+        size = os.path.getsize(src)
+        file_like = open(src, "rb")
+
+    # attach a size() method, so consumers can know the file size
+    file_like.size = lambda : size
+    yield file_like
+    file_like.close()
+
+
 class SerialTransport(Transport):
     def __init__(self, device, baudrate=115200, wait=0, exclusive=True):
         self.in_raw_repl = False
@@ -405,11 +423,12 @@ class SerialTransport(Transport):
         self.exec("f.close()")
 
     def fs_put(self, src, dest, chunk_size=256, progress_callback=None):
-        if progress_callback:
-            src_size = os.path.getsize(src)
-            written = 0
+
         self.exec("f=open('%s','wb')\nw=f.write" % dest)
-        with open(src, "rb") as f:
+        with open_file(src) as f:
+            if progress_callback:
+                src_size = f.size()
+                written = 0
             while True:
                 data = f.read(chunk_size)
                 if not data: