Add information on selecting quicklook data for download

Closes #2 (closed)

Needs a rerender still and possible other cleanups.

cgi-bin~/iqeye/ls.cgi

+#!/var/www/wsgi/python-env/metobs/bin/python
+"""List available EyeQ Camera images.
+
+See `print_usage()` for more information
+"""
+
+import cgi
+import cgitb; cgitb.enable()
+
+import os
+import sys
+from datetime import datetime
+from datetime import timedelta
+
+from metobs import mytime
+
+form = cgi.FieldStorage()
+
+def get(name, default=None):
+    if form.has_key(name):
+        return form[name].value
+    return default
+
+def print_usage():
+    print "ContentType: text/plain"
+    print 
+    print """Provides image listings of SSEC RIG EyeQ Camera images.
+
+Because the images may not be exactly spaced, being that processing may increase
+the interval, images are listed by searching between the date provided and that
+date plus the image resolution.
+
+Parameters
+==========
+
+cam - (required) Camera name. West, East, etc ...
+d   - Date of image in CST (YYYY-MM-DD HH:MM:SS). Defaults to current time.
+"""
+
+#: resolution at which images are generated
+image_rez = 10
+#: timezone for image filename times
+image_tz = mytime.OffsetTimezone(6)
+hostname = 'tahiti.ssec.wisc.edu'
+
+#: convert a file path to a server path`
+url_for = lambda fpth: "http://"+hostname+fpth.replace("/beach", "/pub")
+
+def image_path(cam, dt):
+    """Get a path for an image on disk.
+
+    :param cam: Name of the camera
+    :param dt: datetime of the image file used to parse the name
+    """
+    basedir = '/beach/incoming/Instrument_Data/METOBS/RIG/Cameras'
+    return os.path.join(basedir, cam + dt.strftime('/%Y/%m/%d/%H_%M_%S.trig+00.jpg'))
+
+
+
+#
+#
+# You shouldn't need to change anything below here
+#
+#
+
+
+def redirect_to(url):
+    print "Status: 302 Moved"
+    print "Location: " + url
+    print 
+
+def file_not_found():
+    print "Status: 404 File Not Found"
+    print 
+
+def headers(typ='plain'):
+    print "ContentType: text/" + typ
+    print 
+
+def main():
+
+    # required parameter    
+    camera = get('cam')
+    if not camera:
+        print_usage()
+        return 1
+
+    # parse data from parameter, defaulting to current time in the
+    # timezone specified
+    date = get('d')
+    if not date:
+        date = mytime.utc_now() 
+        date = mytime.set_tz(date, tz=image_tz)
+    else:
+        date = mytime.parse_stamp(date)
+        date = mytime.set_tz(date, tz=image_tz)
+   
+    # images may not be exactly the same interval appart, therefore we have
+    # to attempt to locate the image 
+    url = ""
+    pths = []
+    for i in range(image_rez):
+        fpth = image_path(camera, date + timedelta(seconds=i))
+        pths.append(fpth)
+        if os.path.exists(fpth):
+            url = url_for(fpth)
+            break 
+    
+    # successfully found an image        
+    if url:
+        redirect_to(url)
+
+    if form.has_key('debug'):
+        headers()
+        for pth in pths:
+            print pth
+        return 1
+
+    # we should only get here if the file was not found
+    file_not_found() 
+    return 1
+
+sys.exit(main())