Kivy Garden - Fixed to fertile land again

Kivy fascinates me when it comes to a python UI framework. However while I was installing the pre-requisites I was looking for a kivy-designer which is thankfully available on github.

https://github.com/kivy/kivy-designer

This chap requires the garden and filebrowser class from the kivy garden which is suppose to be downloaded by the garden script which is nothing but a python script. The moment I started setting up the bloke I get

$ garden install filebrowser
Downloading http://github.com/kivy-garden/garden.filebrowser/archive/master.zip ...
Traceback (most recent call last):
  File "/home/addy/workspace/kivyenv/bin/garden", line 190, in <module>
    GardenTool().main(sys.argv[1:])
  File "/home/addy/workspace/kivyenv/bin/garden", line 72, in main
    options.func()
  File "/home/addy/workspace/kivyenv/bin/garden", line 110, in cmd_install
    fd = self.download(opts.package)
  File "/home/addy/workspace/kivyenv/bin/garden", line 171, in download
    data += buf
TypeError: Can't convert 'bytes' object to str implicitly

The problem is with the download call. The initial data buffer is initialized as a str object. The 'r' is a variable which contains the request library's download request data which would a sequence of bytes.  Ultimately the goal is to pass the in-memory binary streams as a zipfile. However python 3 will not let us convert the bytes to str directly.  Observe the following code 

    def download(self, package):

        url = 'http://github.com/kivy-garden/{}/archive/master.zip'.format(

                package)

        print('Downloading {} ...'.format(url))

        r = requests.get(url)#, prefetch=False) # r is requests library's download content 

        if r.status_code != 200:

            print('Unable to found the garden package. (error={})'.format(

                r.status_code))

            sys.exit(1)

        animation = '\\|/-'

        index = 0

        count = 0

        data = '' # problem 1 

#the loop is basically re-assembling the binary stream 

        for buf in r.iter_content(1024):

            index += 1

            data += buf  ## this is what is throwing the exception 

            count += len(buf)

            print('Progression', count, animation[index % len(animation)], '\r')

            sys.stdout.flush()

        print('Download done ({} downloaded)'.format(count))

        

        return StringIO(data) ## why aren't we returning binary data 

Potential fix to the problem which finally worked 

# add the import to the top of the file. 

    from io import BytesIO

    def download(self, package):

        url = 'http://github.com/kivy-garden/{}/archive/master.zip'.format(

                package)

        print('Downloading {} ...'.format(url))

        r = requests.get(url)#, prefetch=False)

        if r.status_code != 200:

            print('Unable to found the garden package. (error={})'.format(

                r.status_code))

            sys.exit(1)

        animation = '\\|/-'

        index = 0

        count = 0

        data = b'' #this takes care of the string conversion

        for buf in r.iter_content(1024):

            index += 1

            data += buf  # no more error here 

            count += len(buf)

            print('Progression', count, animation[index % len(animation)], '\r')

            sys.stdout.flush()

        print('Download done ({} downloaded)'.format(count))

        

        return BytesIO(data) #return a byte stream than a string stream 

Wallah !! all works now !! 

$ garden install filebrowser

Downloading http://github.com/kivy-garden/garden.filebrowser/archive/master.zip ...

Progression 1024 | 

...... snppped ... 

Progression 206959 - 

Download done (206959 downloaded)

Extracting...

Installing new version...

Done! garden.filebrowser is installed at: /home/addy/.kivy/garden/garden.filebrowser

Cleaning...