provide hostname hint in editor temporary files

when calling an external editor, include the hostname of the remote
site in the generated temporary filename.

Closes #495

native/native_main.py

@@ -4,12 +4,15 @@
 import sys
 import os
 import json
+import re
 import struct
 import subprocess
 import tempfile
+import unicodedata
 
 VERSION = "0.1.3"
 
+
 class NoConnectionError(Exception):
     """ Exception thrown when stdin cannot be read """
 
@@ -25,6 +28,7 @@ def getenv(variable, default):
     """ Get an environment variable value, or use the default provided """
     return os.environ.get(variable) or default
 
+
 def getMessage():
     """Read a message from stdin and decode it.
 
@@ -101,6 +105,19 @@ def getUserConfig():
     return open(cfg_file, 'r').read()
 
 
+def sanitizeFilename(fn):
+    """ Transform a string to make it suitable for use as a filename.
+
+    From https://stackoverflow.com/a/295466/147356"""
+
+    fn = unicodedata.normalize('NFKD', fn).encode(
+        'ascii', 'ignore').decode('ascii')
+    fn = re.sub('[^\w\s/.-]', '', fn).strip().lower()
+    fn = re.sub('\.\.+', '', fn)
+    fn = re.sub('[-/\s]+', '-', fn)
+    return fn
+
+
 def handleMessage(message):
     """ Generate reply from incoming message. """
     cmd = message["cmd"]
@@ -153,7 +170,11 @@ def handleMessage(message):
             file.write(message["content"])
 
     elif cmd == 'temp':
-        (handle, filepath) = tempfile.mkstemp()
+        prefix = message.get('prefix')
+        if prefix is not None:
+            prefix = 'tmp_{}_'.format(sanitizeFilename(prefix))
+
+        (handle, filepath) = tempfile.mkstemp(prefix=prefix)
         with os.fdopen(handle, "w") as file:
             file.write(message["content"])
         reply['content'] = filepath

src/excmds.ts

@@ -167,8 +167,9 @@ export async function getinput() {
  */
 //#background
 export async function editor() {
+    let url = new URL((await activeTab()).url)
     if (!await Native.nativegate()) return
-    const file = (await Native.temp(await getinput())).content
+    const file = (await Native.temp(await getinput(), url.hostname)).content
     fillinput((await Native.editor(file)).content)
     // TODO: add annoying "This message was written with [Tridactyl](https://addons.mozilla.org/en-US/firefox/addon/tridactyl-vim/)"
     // to everything written using editor

src/native_background.ts

@@ -238,8 +238,8 @@ export async function mkdir(dir: string, exist_ok: boolean) {
     return sendNativeMsg("mkdir", { dir, exist_ok })
 }
 
-export async function temp(content: string) {
+export async function temp(content: string, prefix: string) {
-    return sendNativeMsg("temp", { content })
+    return sendNativeMsg("temp", { content, prefix })
 }
 
 export async function run(command: string) {