Add in a dotcloud-based thumbnailing service; most of this code is ea…

…sily

reusable, but it's specifically all you need to get set up with dotcloud.

accesstools/dotcloud-thumbnail/postinstall

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+if [ ! -f $HOME/env/bin/curl-config ]; then
+    wget -c http://curl.haxx.se/download/curl-7.21.6.tar.gz
+    tar -zvxf curl-7.21.6.tar.gz
+    cd curl-7.21.6
+    ./configure --prefix=$HOME --bindir=$HOME/env/bin
+    make 
+    make install
+    cd ..
+fi
+
+if [ ! -f $HOME/env/bin/gdal-config ]; then
+    wget -c http://download.osgeo.org/gdal/gdal-1.8.0.tar.gz
+    tar -zvxf gdal-1.8.0.tar.gz
+    cd gdal-1.8.0
+    LIBS="`curl-config --libs`" ./configure --prefix=$HOME --bindir=$HOME/env/bin --with-curl --without-libtool --with-python
+    make
+    make install
+    cd ..
+fi    

accesstools/dotcloud-thumbnail/requirements.txt

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+Pil
+redis

accesstools/dotcloud-thumbnail/settings.py

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+# the following information is available via 'dotcloud info yourhost.redis'
+redis_host="redis.yourhost.dotcloud.com"
+redis_port=None # port
+redis_password=None # password 
+

accesstools/dotcloud-thumbnail/supervisord.conf

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+[program:uwsgi]
+directory=/home/dotcloud/current
+command=/usr/bin/uwsgi --pidfile /var/dotcloud/uwsgi.pid -s /var/dotcloud/uwsgi.sock --chmod-socket=660 --master --processes 1 --home /home/dotcloud/env --pythonpath /home/dotcloud/current --disable-logging
+autostart=true
+autorestart=true
+stdout_logfile=/var/log/supervisor/uwsgi.log
+stderr_logfile=/var/log/supervisor/uwsgi.log
+stopsignal=INT
+environment=LD_LIBRARY_PATH="/home/dotcloud/lib"

accesstools/dotcloud-thumbnail/wsgi.py

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+import os
+import urllib
+import json
+import gdal
+import Image
+import gdal
+import math
+from StringIO import StringIO
+import cgi
+import redis
+import settings
+
+OAM_HOST = "oam.osgeo.org"
+
+# The following two functions were provided by 
+# Michael Migurski, as part of the OpenAerialMap 
+# server code.
+
+def image_size_small(im_width, im_height, size):
+    """ Determine a good thumbnail size based on desired named size.
+    """
+    aspect = float(im_width) / float(im_height)
+
+    if size == 'thumbnail':
+        if aspect > 1.6:
+            return 440, int(440 / aspect)
+        elif aspect < .3:
+            return 98, int(98 / aspect)
+        else:
+            return 196, int(196 / aspect)
+    
+    elif size == 'preview':
+        area = 320 * 320
+    elif size == 'large':
+        area = 640 * 640
+    else:
+        raise Exception('Don\'t know about "%s"' % size)
+    
+    th_height = int(math.sqrt(area / aspect))
+    th_width = int(aspect * th_height)
+    
+    return th_width, th_height
+
+def image_made_smaller(im, size="preview"):
+    """
+    """
+    os.environ['GDAL_DISABLE_READDIR_ON_OPEN'] = 'YES'
+    #environ['CPL_DEBUG'] = 'On'
+
+    ds = gdal.Open('/vsicurl/' + im)
+    th_width, th_height = image_size_small(ds.RasterXSize, ds.RasterYSize, size)
+    
+    #
+    # Extract the best-sized overview from the source image
+    #
+    interps = dict([(getattr(gdal, gci), gci[4:-4]) for gci in dir(gdal) if gci.startswith('GCI')])
+    bands = dict([(interps[ds.GetRasterBand(i).GetColorInterpretation()], ds.GetRasterBand(i)) for i in range(1, 1 + ds.RasterCount)])
+    chans = []
+    
+    for (chan, interp) in enumerate(('Red', 'Green', 'Blue')):
+        assert interp in bands, '%s missing from bands - bad news.' % interp
+
+        band = bands[interp]
+        overviews = [band.GetOverview(i) for i in range(band.GetOverviewCount())]
+        overviews = [(ov.XSize, ov.YSize, ov) for ov in overviews]
+        
+        for (ov_width, ov_height, overview) in sorted(overviews):
+            if ov_width > th_width:
+                data = overview.ReadRaster(0, 0, ov_width, ov_height)
+                chan = Image.fromstring('L', (ov_width, ov_height), data)
+                chan = chan.resize((th_width, th_height), Image.ANTIALIAS)
+
+                chans.append(chan)
+                break
+    
+    #
+    # Return an image
+    #
+    thumb = Image.merge('RGB', chans)
+
+    return thumb
+
+
+def application(environ, start_response):
+    red = redis.Redis(host=settings.redis_host, port=settings.redis_port, db=0, password=settings.redis_password)
+    form = cgi.FieldStorage(fp=environ['wsgi.input'], 
+                        environ=environ)
+    if 'id' in form:
+        id = form["id"].value
+        if 'size' in form:
+            size = form['size'].value
+        else:
+            size = 'thumbnail'
+        output = red.get("%s-%s" % (id, size))
+        if not output:
+            image = urllib.urlopen("http://%s/api/image/%s/" % (OAM_HOST, id))
+            data = json.loads(image.read())
+            preview = image_made_smaller(data['url'], size)
+            buffer = StringIO()
+            preview.save(buffer, 'JPEG')
+            output = buffer.getvalue()
+            red.set("%s-%s" % (id, size), output)
+        status = '200 OK'
+        response_headers = [('Content-type', 'image/jpeg'),
+                            ('Content-Length', str(len(output)))]
+        start_response(status, response_headers)
+    else:
+        output = "OAM Thumbnailing code."
+        response_headers = [('Content-type', 'text/plain'),
+                            ('Content-Length', str(len(output)))]
+        start_response(status, response_headers)
+
+    return [output]