Refactored a little. Now the image type and dimensions detection is a

separate function.

lib/python/OFS/Image.py

@@ -84,7 +84,7 @@
 ##############################################################################
 """Image object"""
 
-__version__='$Revision: 1.122 $'[11:-2]
+__version__='$Revision: 1.123 $'[11:-2]
 
 import Globals, string, struct, content_types
 from OFS.content_types import guess_content_type
@@ -443,6 +443,64 @@ def manage_addImage(self, id, file, title='', precondition='', content_type='',
         REQUEST.RESPONSE.redirect('%s/manage_main' % url)
     return id
 
+
+def getImageInfo(data):
+    data = str(data)
+    size = len(data)
+    height = -1
+    width = -1
+    content_type = ''
+
+    # handle GIFs   
+    if (size >= 10) and data[:6] in ('GIF87a', 'GIF89a'):
+        # Check to see if content_type is correct
+        content_type = 'image/gif'
+        w, h = struct.unpack("<HH", data[6:10])
+        width = int(w)
+        height = int(h)
+
+    # See PNG v1.2 spec (http://www.cdrom.com/pub/png/spec/)
+    # Bytes 0-7 are below, 4-byte chunk length, then 'IHDR'
+    # and finally the 4-byte width, height
+    elif ((size >= 24) and (data[:8] == '\211PNG\r\n\032\n')
+          and (data[12:16] == 'IHDR')):
+        content_type = 'image/png'
+        w, h = struct.unpack(">LL", data[16:24])
+        width = int(w)
+        height = int(h)
+            
+    # Maybe this is for an older PNG version.
+    elif (size >= 16) and (data[:8] == '\211PNG\r\n\032\n'):
+        # Check to see if we have the right content type
+        content_type = 'image/png'
+        w, h = struct.unpack(">LL", data[8:16])
+        width = int(w)
+        height = int(h)
+
+    # handle JPEGs
+    elif (size >= 2) and (data[:2] == '\377\330'):
+        content_type = 'image/jpeg'
+        jpeg = StringIO(data)
+        jpeg.read(2)
+        b = jpeg.read(1)
+        try:
+            while (b and ord(b) != 0xDA):
+                while (ord(b) != 0xFF): b = jpeg.read(1)
+                while (ord(b) == 0xFF): b = jpeg.read(1)
+                if (ord(b) >= 0xC0 and ord(b) <= 0xC3):
+                    jpeg.read(3)
+                    h, w = struct.unpack(">HH", jpeg.read(4))
+                    break
+                else:
+                    jpeg.read(int(struct.unpack(">H", jpeg.read(2))[0])-2)
+                b = jpeg.read(1)
+            width = int(w)
+            height = int(h)
+        except: pass
+
+    return content_type, width, height
+
+
 class Image(File):
     """Image objects can be GIF, PNG or JPEG and have the same methods
     as File objects.  Images also have a string representation that
@@ -503,68 +561,14 @@ class Image(File):
 
         self.size=size
         self.data=data
-        data=str(data)
-
-        # handle GIFs   
-        if (size >= 10) and data[:6] in ('GIF87a', 'GIF89a'):
-            # Check to see if content_type is correct
-            if content_type != 'image/gif':
-                content_type = 'image/gif'
-            w, h = struct.unpack("<HH", data[6:10])
-            self.width=str(int(w))
-            self.height=str(int(h))
-
-        # handle JPEGs
-        elif (size >= 2) and (data[:2] == '\377\330'):
-            jpeg=StringIO(data)
-            jpeg.read(2)
-            b=jpeg.read(1)
-            try:
-                while (b and ord(b) != 0xDA):
-                    while (ord(b) != 0xFF): b = jpeg.read(1)
-                    while (ord(b) == 0xFF): b = jpeg.read(1)
-                    if (ord(b) >= 0xC0 and ord(b) <= 0xC3):
-                        jpeg.read(3)
-                        h, w = struct.unpack(">HH", jpeg.read(4))
-                        break
-                    else:
-                        jpeg.read(int(struct.unpack(">H", jpeg.read(2))[0])-2)
-                    b = jpeg.read(1)
-                self.width=str(int(w))
-                self.height=str(int(h))
-            except: pass
-
-            # Check to see if we have the right content type
-            if content_type != 'image/jpeg':
-                content_type = 'image/jpeg'
-            
-        # handle PNGs
-
-        # Someone says this is the right thing:
-
-        # Re: PNG v1.2 spec (http://www.cdrom.com/pub/png/spec/)
-        # Bytes 0-7 are below, 4-byte chunk length, then 'IHDR'
-        # and finally the 4-byte width, height
-        elif (size >= 24) and (data[:8] == '\211PNG\r\n\032\n') \
-           and (data[12:16] == 'IHDR'):
-            # Check to see if we have the right content type
-            if content_type != 'image/png':
-                content_type = 'image/png'
-            w, h = struct.unpack(">LL", data[16:24])
-            self.width=str(int(w))
-            self.height=str(int(h))
-            
-        # But we had this before. I have no clue, so I'll keep both. :)
-        # Maybe this is for an older PNG version.
-        elif (size >= 16) and (data[:8] == '\x89PNG\r\n\x1a\n'):
-            # Check to see if we have the right content type
-            if content_type != 'image/png':
-                content_type = 'image/png'
-
-            w, h = struct.unpack(">LL", data[8:16])
-            self.width=str(int(w))
-            self.height=str(int(h))
-            
+
+        ct, width, height = getImageInfo(data)
+        if ct:
+            content_type = ct
+        if width >= 0 and height >= 0:
+            self.width = width
+            self.height = height
+
         # Now we should have the correct content type, or still None
         if content_type is not None: self.content_type = content_type