python bottle route with regex not matching - 404 error

Question

I'm trying to setup a python camera app that streams to a browser and am using bottle. My javascript in the index.html is this:

<div class="panel-body"> <img src="stream/d" onload="imageRefresh(this, 30);" style="max-width: 100%;">

The imageRefresh function uses setTimeout and it takes the image url and appends a time value to it so that it is unique and the browser will fire off a request to the server. This process worked fine with a server I found on the internet called microwebsrv which is on github at: https://github.com/jczic/MicroWebSrv; however, I'm trying to move over to bottle on my raspberry pi. My routes for bottle look like this:

@route('/stream/d')
@route('/stream/<val:re:d[\d]+>')
def _httpStream(val="d")
  print("val: %s" % val)
  (rest of code here)

However, after the very first image is served (I see the image flash on the browser screen and in on the developer console I see http://192.168.0.18:8080/stream/d; I also see the "GET /stream/d" on the rPi terminal from which I launched the app) then the next get request which looks like: http://192.168.0.18:8080/stream/d1633472974918 fails with a 404 error, I presume because the route isn't matching? I have also tried by simply using a route like: @route(/stream/) but I still get the same error. The imageRefresh function updates the img.src like this:

img.src=http + '/d' + d.getTime();

I've read the bottle docs a number of times and I've tested my regex with a "regex Regular Expression Tool" I installed from the Windows store. The regex tool shows it matches.

Answer 1

Maybe the problem is that you have specified two routes but only one specifies variable name val and this is an inconsistency. I am no expert in Bottle , but you might try the following:

@route('/stream/<val:re:d[\d]*>')
def _httpStream(val="d")
  print("val: %s" % val)
  (rest of code here)

This now allows 0 or more digits after the 'd'.

By the way, your regex could also have been more simply specified as d\d* .

Update

I created the following simple program...

from bottle import route, run

@route('/stream/<val:re:d[\d]*>')
def hello(val):
    return val

run(host='localhost', port=8080, debug=True)

... and everything worked as expected. I should add that specifying two routes with a default value for argument val also works:

from bottle import route, run

@route('/stream/d>')
@route('/stream/<val:re:d[\d]+>')
def hello(val="d"):
    return val

run(host='localhost', port=8080, debug=True)

Answer 2

I finally figured it out, Firstly. I put this particular route first in the program, Then: I changed the routes to be:

    @app.route('/stream/<time>')
    
    @app.route('/stream/<time:re:d.*>')

This took care of the 404 problem and now I'm able to stream images captured from a camera. Thanks for the suggestions above, I also upgraded to 0.13-dev and changed my simplified my regex.