import python with __main__ method

Question

I have a python script that have __main__ statement and took all values parametric. I want to import and use it in my own script.

Actually I can import but don't know how to use it.

As you see below, __main__ is a bit complicated and rewriting it will take time because I even don't know what does most of code mean.

Want to know is there any way to import and use the code as a function?

import os
import sys
import time
import base64
from urllib2 import urlopen
from urllib2 import Request
from urllib2 import HTTPError
from urllib import urlencode
from urllib import quote
from exceptions import Exception
from email.mime.multipart import MIMEMultipart

from email.mime.base import MIMEBase
from email.mime.application  import MIMEApplication

from email.encoders import encode_noop

from api_util import json2python, python2json

class MalformedResponse(Exception):
    pass
class RequestError(Exception):
    pass

class Client(object):
    default_url = 'http://nova.astrometry.net/api/'

    def __init__(self,
                 apiurl = default_url):
        self.session = None
        self.apiurl = apiurl

    def get_url(self, service):
        return self.apiurl + service

    def send_request(self, service, args={}, file_args=None):
        '''
        service: string
        args: dict
        '''
        if self.session is not None:
            args.update({ 'session' : self.session })
        print 'Python:', args
        json = python2json(args)
        print 'Sending json:', json
        url = self.get_url(service)
        print 'Sending to URL:', url

        # If we're sending a file, format a multipart/form-data
        if file_args is not None:
            m1 = MIMEBase('text', 'plain')
            m1.add_header('Content-disposition', 'form-data; name="request-json"')
            m1.set_payload(json)

            m2 = MIMEApplication(file_args[1],'octet-stream',encode_noop)
            m2.add_header('Content-disposition',
                          'form-data; name="file"; filename="%s"' % file_args[0])

            #msg.add_header('Content-Disposition', 'attachment',
            # filename='bud.gif')
            #msg.add_header('Content-Disposition', 'attachment',
            # filename=('iso-8859-1', '', 'FuSballer.ppt'))

            mp = MIMEMultipart('form-data', None, [m1, m2])

            # Makie a custom generator to format it the way we need.
            from cStringIO import StringIO
            from email.generator import Generator

            class MyGenerator(Generator):
                def __init__(self, fp, root=True):
                    Generator.__init__(self, fp, mangle_from_=False,
                                       maxheaderlen=0)
                    self.root = root
                def _write_headers(self, msg):
                    # We don't want to write the top-level headers;
                    # they go into Request(headers) instead.
                    if self.root:
                        return                        
                    # We need to use \r\n line-terminator, but Generator
                    # doesn't provide the flexibility to override, so we
                    # have to copy-n-paste-n-modify.
                    for h, v in msg.items():
                        print >> self._fp, ('%s: %s\r\n' % (h,v)),
                    # A blank line always separates headers from body
                    print >> self._fp, '\r\n',

                # The _write_multipart method calls "clone" for the
                # subparts.  We hijack that, setting root=False
                def clone(self, fp):
                    return MyGenerator(fp, root=False)

            fp = StringIO()
            g = MyGenerator(fp)
            g.flatten(mp)
            data = fp.getvalue()
            headers = {'Content-type': mp.get('Content-type')}

            if False:
                print 'Sending headers:'
                print ' ', headers
                print 'Sending data:'
                print data[:1024].replace('\n', '\\n\n').replace('\r', '\\r')
                if len(data) > 1024:
                    print '...'
                    print data[-256:].replace('\n', '\\n\n').replace('\r', '\\r')
                    print

        else:
            # Else send x-www-form-encoded
            data = {'request-json': json}
            print 'Sending form data:', data
            data = urlencode(data)
            print 'Sending data:', data
            headers = {}

        request = Request(url=url, headers=headers, data=data)

        try:
            f = urlopen(request)
            txt = f.read()
            print 'Got json:', txt
            result = json2python(txt)
            print 'Got result:', result
            stat = result.get('status')
            print 'Got status:', stat
            if stat == 'error':
                errstr = result.get('errormessage', '(none)')
                raise RequestError('server error message: ' + errstr)
            return result
        except HTTPError, e:
            print 'HTTPError', e
            txt = e.read()
            open('err.html', 'wb').write(txt)
            print 'Wrote error text to err.html'

    def login(self, apikey):
        args = { 'apikey' : apikey }
        result = self.send_request('login', args)
        sess = result.get('session')
        print 'Got session:', sess
        if not sess:
            raise RequestError('no session in result')
        self.session = sess

    def _get_upload_args(self, **kwargs):
        args = {}
        for key,default,typ in [('allow_commercial_use', 'd', str),
                                ('allow_modifications', 'd', str),
                                ('publicly_visible', 'y', str),
                                ('scale_units', None, str),
                                ('scale_type', None, str),
                                ('scale_lower', None, float),
                                ('scale_upper', None, float),
                                ('scale_est', None, float),
                                ('scale_err', None, float),
                                ('center_ra', None, float),
                                ('center_dec', None, float),
                                ('radius', None, float),
                                ('downsample_factor', None, int),
                                ('tweak_order', None, int),
                                ('crpix_center', None, bool),
                                # image_width, image_height
                                ]:
            if key in kwargs:
                val = kwargs.pop(key)
                val = typ(val)
                args.update({key: val})
            elif default is not None:
                args.update({key: default})
        print 'Upload args:', args
        return args

    def url_upload(self, url, **kwargs):
        args = dict(url=url)
        args.update(self._get_upload_args(**kwargs))
        result = self.send_request('url_upload', args)
        return result

    def upload(self, fn, **kwargs):
        args = self._get_upload_args(**kwargs)
        try:
            f = open(fn, 'rb')
            result = self.send_request('upload', args, (fn, f.read()))
            return result
        except IOError:
            print 'File %s does not exist' % fn     
            raise

    def submission_images(self, subid):
        result = self.send_request('submission_images', {'subid':subid})
        return result.get('image_ids')

    def overlay_plot(self, service, outfn, wcsfn, wcsext=0):
        from astrometry.util import util as anutil
        wcs = anutil.Tan(wcsfn, wcsext)
        params = dict(crval1 = wcs.crval[0], crval2 = wcs.crval[1],
                      crpix1 = wcs.crpix[0], crpix2 = wcs.crpix[1],
                      cd11 = wcs.cd[0], cd12 = wcs.cd[1],
                      cd21 = wcs.cd[2], cd22 = wcs.cd[3],
                      imagew = wcs.imagew, imageh = wcs.imageh)
        result = self.send_request(service, {'wcs':params})
        print 'Result status:', result['status']
        plotdata = result['plot']
        plotdata = base64.b64decode(plotdata)
        open(outfn, 'wb').write(plotdata)
        print 'Wrote', outfn

    def sdss_plot(self, outfn, wcsfn, wcsext=0):
        return self.overlay_plot('sdss_image_for_wcs', outfn,
                                 wcsfn, wcsext)

    def galex_plot(self, outfn, wcsfn, wcsext=0):
        return self.overlay_plot('galex_image_for_wcs', outfn,
                                 wcsfn, wcsext)

    def myjobs(self):
        result = self.send_request('myjobs/')
        return result['jobs']

    def job_status(self, job_id, justdict=False):
        result = self.send_request('jobs/%s' % job_id)
        if justdict:
            return result
        stat = result.get('status')
        if stat == 'success':
            result = self.send_request('jobs/%s/calibration' % job_id)
            print 'Calibration:', result
            result = self.send_request('jobs/%s/tags' % job_id)
            print 'Tags:', result
            result = self.send_request('jobs/%s/machine_tags' % job_id)
            print 'Machine Tags:', result
            result = self.send_request('jobs/%s/objects_in_field' % job_id)
            print 'Objects in field:', result
            result = self.send_request('jobs/%s/annotations' % job_id)
            print 'Annotations:', result
            result = self.send_request('jobs/%s/info' % job_id)
            print 'Calibration:', result

        return stat

    def sub_status(self, sub_id, justdict=False):
        result = self.send_request('submissions/%s' % sub_id)
        if justdict:
            return result
        return result.get('status')

    def jobs_by_tag(self, tag, exact):
        exact_option = 'exact=yes' if exact else ''
        result = self.send_request(
            'jobs_by_tag?query=%s&%s' % (quote(tag.strip()), exact_option),
            {},
        )
        return result

if __name__ == '__main__':
    import optparse
    parser = optparse.OptionParser()
    parser.add_option('--server', dest='server', default=Client.default_url,
                      help='Set server base URL (eg, %default)')
    parser.add_option('--apikey', '-k', dest='apikey',
                      help='API key for Astrometry.net web service; if not given will check AN_API_KEY environment variable')
    parser.add_option('--upload', '-u', dest='upload', help='Upload a file')
    parser.add_option('--wait', '-w', dest='wait', action='store_true', help='After submitting, monitor job status')
    parser.add_option('--wcs', dest='wcs', help='Download resulting wcs.fits file, saving to given filename; implies --wait if --urlupload or --upload')
    parser.add_option('--kmz', dest='kmz', help='Download resulting kmz file, saving to given filename; implies --wait if --urlupload or --upload')
    parser.add_option('--urlupload', '-U', dest='upload_url', help='Upload a file at specified url')
    parser.add_option('--scale-units', dest='scale_units',
                      choices=('arcsecperpix', 'arcminwidth', 'degwidth', 'focalmm'), help='Units for scale estimate')
    #parser.add_option('--scale-type', dest='scale_type',
    #                  choices=('ul', 'ev'), help='Scale bounds: lower/upper or estimate/error')
    parser.add_option('--scale-lower', dest='scale_lower', type=float, help='Scale lower-bound')
    parser.add_option('--scale-upper', dest='scale_upper', type=float, help='Scale upper-bound')
    parser.add_option('--scale-est', dest='scale_est', type=float, help='Scale estimate')
    parser.add_option('--scale-err', dest='scale_err', type=float, help='Scale estimate error (in PERCENT), eg "10" if you estimate can be off by 10%')
    parser.add_option('--ra', dest='center_ra', type=float, help='RA center')
    parser.add_option('--dec', dest='center_dec', type=float, help='Dec center')
    parser.add_option('--radius', dest='radius', type=float, help='Search radius around RA,Dec center')
    parser.add_option('--downsample', dest='downsample_factor', type=int, help='Downsample image by this factor')
    parser.add_option('--parity', dest='parity', choices=('0','1'), help='Parity (flip) of image')
    parser.add_option('--tweak-order', dest='tweak_order', type=int, help='SIP distortion order (default: 2)')
    parser.add_option('--crpix-center', dest='crpix_center', action='store_true', default=None, help='Set reference point to center of image?')
    parser.add_option('--sdss', dest='sdss_wcs', nargs=2, help='Plot SDSS image for the given WCS file; write plot to given PNG filename')
    parser.add_option('--galex', dest='galex_wcs', nargs=2, help='Plot GALEX image for the given WCS file; write plot to given PNG filename')
    parser.add_option('--substatus', '-s', dest='sub_id', help='Get status of a submission')
    parser.add_option('--jobstatus', '-j', dest='job_id', help='Get status of a job')
    parser.add_option('--jobs', '-J', dest='myjobs', action='store_true', help='Get all my jobs')
    parser.add_option('--jobsbyexacttag', '-T', dest='jobs_by_exact_tag', help='Get a list of jobs associated with a given tag--exact match')
    parser.add_option('--jobsbytag', '-t', dest='jobs_by_tag', help='Get a list of jobs associated with a given tag')
    parser.add_option( '--private', '-p',
        dest='public',
        action='store_const',
        const='n',
        default='y',
        help='Hide this submission from other users')
    parser.add_option('--allow_mod_sa','-m',
        dest='allow_mod',
        action='store_const',
        const='sa',
        default='d',
        help='Select license to allow derivative works of submission, but only if shared under same conditions of original license') 
    parser.add_option('--no_mod','-M',
        dest='allow_mod',
        action='store_const',
        const='n',
        default='d',
        help='Select license to disallow derivative works of submission')
    parser.add_option('--no_commercial','-c',
        dest='allow_commercial',
        action='store_const',
        const='n',
        default='d',
        help='Select license to disallow commercial use of submission') 
    opt,args = parser.parse_args()

    if opt.apikey is None:
        # try the environment
        opt.apikey = os.environ.get('AN_API_KEY', None)
    if opt.apikey is None:
        parser.print_help()
        print
        print 'You must either specify --apikey or set AN_API_KEY'
        sys.exit(-1)

    args = {}
    args['apiurl'] = opt.server
    c = Client(**args)
    c.login(opt.apikey)

    if opt.upload or opt.upload_url:
        if opt.wcs or opt.kmz:
            opt.wait = True

        kwargs = dict(
            allow_commercial_use=opt.allow_commercial,
            allow_modifications=opt.allow_mod,
            publicly_visible=opt.public)
        if opt.scale_lower and opt.scale_upper:
            kwargs.update(scale_lower=opt.scale_lower,
                          scale_upper=opt.scale_upper,
                          scale_type='ul')
        elif opt.scale_est and opt.scale_err:
            kwargs.update(scale_est=opt.scale_est,
                          scale_err=opt.scale_err,
                          scale_type='ev')
        elif opt.scale_lower or opt.scale_upper:
            kwargs.update(scale_type='ul')
            if opt.scale_lower:
                kwargs.update(scale_lower=opt.scale_lower)
            if opt.scale_upper:
                kwargs.update(scale_upper=opt.scale_upper)

        for key in ['scale_units', 'center_ra', 'center_dec', 'radius',
                    'downsample_factor', 'tweak_order', 'crpix_center',]:
            if getattr(opt, key) is not None:
                kwargs[key] = getattr(opt, key)
        if opt.parity is not None:
            kwargs.update(parity=int(opt.parity))

        if opt.upload:
            upres = c.upload(opt.upload, **kwargs)
        if opt.upload_url:
            upres = c.url_upload(opt.upload_url, **kwargs)

        stat = upres['status']
        if stat != 'success':
            print 'Upload failed: status', stat
            print upres
            sys.exit(-1)

        opt.sub_id = upres['subid']

    if opt.wait:
        if opt.job_id is None:
            if opt.sub_id is None:
                print "Can't --wait without a submission id or job id!"
                sys.exit(-1)

            while True:
                stat = c.sub_status(opt.sub_id, justdict=True)
                print 'Got status:', stat
                jobs = stat.get('jobs', [])
                if len(jobs):
                    for j in jobs:
                        if j is not None:
                            break
                    if j is not None:
                        print 'Selecting job id', j
                        opt.job_id = j
                        break
                time.sleep(5)

        success = False
        while True:
            stat = c.job_status(opt.job_id, justdict=True)
            print 'Got job status:', stat
            if stat.get('status','') in ['success']:
                success = (stat['status'] == 'success')
                break
            time.sleep(5)

        if success:
            c.job_status(opt.job_id)
            # result = c.send_request('jobs/%s/calibration' % opt.job_id)
            # print 'Calibration:', result
            # result = c.send_request('jobs/%s/tags' % opt.job_id)
            # print 'Tags:', result
            # result = c.send_request('jobs/%s/machine_tags' % opt.job_id)
            # print 'Machine Tags:', result
            # result = c.send_request('jobs/%s/objects_in_field' % opt.job_id)
            # print 'Objects in field:', result
            #result = c.send_request('jobs/%s/annotations' % opt.job_id)
            #print 'Annotations:', result

            retrieveurls = []
            if opt.wcs:
                # We don't need the API for this, just construct URL
                url = opt.server.replace('/api/', '/wcs_file/%i' % opt.job_id)
                retrieveurls.append((url, opt.wcs))
            if opt.kmz:
                url = opt.server.replace('/api/', '/kml_file/%i/' % opt.job_id)
                retrieveurls.append((url, opt.kmz))

            for url,fn in retrieveurls:
                print 'Retrieving file from', url, 'to', fn
                f = urlopen(url)
                txt = f.read()
                w = open(fn, 'wb')
                w.write(txt)
                w.close()
                print 'Wrote to', fn


        opt.job_id = None
        opt.sub_id = None

    if opt.sdss_wcs:
        (wcsfn, outfn) = opt.sdss_wcs
        c.sdss_plot(outfn, wcsfn)
    if opt.galex_wcs:
        (wcsfn, outfn) = opt.galex_wcs
        c.galex_plot(outfn, wcsfn)
    if opt.sub_id:
        print c.sub_status(opt.sub_id)
    if opt.job_id:
        print c.job_status(opt.job_id)
        #result = c.send_request('jobs/%s/annotations' % opt.job_id)
        #print 'Annotations:', result

    if opt.jobs_by_tag:
        tag = opt.jobs_by_tag
        print c.jobs_by_tag(tag, None)
    if opt.jobs_by_exact_tag:
        tag = opt.jobs_by_exact_tag
        print c.jobs_by_tag(tag, 'yes')

    if opt.myjobs:
        jobs = c.myjobs()
        print jobs

    #print c.submission_images(1)

Conducive

Answer 1

No, there is no clean way to do so. When the module is being imported, it's code is executed and all global variables are set as attributes to the module object. So if part of the code is not executed at all (is guarded by __main__ condition) there is no clean way to get access to that code. You can however run code of this module with substituted __name__ but that's very hackish.

You should refactor this module and move whole __main__ part into a method and call it like this:

def main():
    do_everything()

if __name__ == '__main__':
    main()

This way consumer apps will be able to run code without having to run it in a separate process.

Inimitable

+1. The reason for refactoring __main__ into a method is because otherwise there are nasty side effects when you import it. – Hanahanae

Answer 2

Use the runpy module in the Python 3 Standard Library

See that data can be passed to and from the called script

# top.py

import runpy
import sys
sys.argv += ["another parameter"]
module_globals_dict = runpy.run_path("other_script.py",
    init_globals = globals(), run_name="__main__")
print(module_globals_dict["return_value"])

# other_script.py

# Note we did not load sys module, it gets passed to this script
script_name = sys.argv[0]

print(f"Script {script_name} loaded")

if __name__ == "__main__":
    params = sys.argv[1:]
    print(f"Script {script_name} run with params: {params}")
    return_value = f"{script_name} Done"

Colossae

Answer 3

by what your saying you want to call a function in the script that is importing the module so try:

import __main__
__main__.myfunc()

Helvetia

import __main__ should not be encouraged for various reasons: #24024101 especially if there are better alternatives as suggested in the other answer. – Cardioid