[ZODB-Dev] Investigating a Zope reference leak... tracking object creation

[Ben Last (ZODBDev)]

Chris Withers wrote:
> My gut reaction is that it's this extenal method that's causing your 
> problems. Is it short enough to post here?

In slightly bastardized form, yes.  This is normally invoked from ZPT using an idiom:
<img tal:replace="structure python:here.scripts.getGraphic(here,environment,'myimage.gif',...)"/>

def getGraphic(here, target, environment, style=None, css_class=None, border=None, wap=False, title=None, alt=None, longdesc=None, **kwargs):
     """Return an object that represents the graphic, with useful
     attributes.  This is rather like looking up the Image (or flash
     file) but is more useful for the site because we can override the tag
     generation code and handle flash-replacement.
     See sitedesign.doc for the rationale that chose not to extend the
     OFS.Image.Image class"""

     request = here.REQUEST
     assert environment, "An environment is required"

     if style:
         #TAL doesn't allow ';' in the source, so we use '$' instead.
         style = style.replace('$',chr(59))

     if flash is None:
         flash = getattr(environment,'flash',False)
     partner = getattr(environment, 'partner', "")

     if target.endswith('.jpg') or target.endswith('.gif'):
         swftarget = target[:-4]
     else:
         swftarget = None

     #Create a dictish object to hold the attributes we return
     graphic = Products.PythonScripts.standard.Object()
     graphic['target'] = target

     #Fix up the tag in case of failure.
     graphic['tag'] = '<img alt="No image" src="/Images/none.jpg"/>'

     img = None

     #Try and find the image.
     #find the partner folder and look up images from there (so that
     #acquisition lets us override stuff).
     imgc = None
     if partner:
         imgc = getattr(here.Images, partner)
     else:
         imgc = here.Images

     #Look up the image.
     img = None
     try:
         graphic['state'] = 'Image not found'
         img = getattr(imgc,target)
         graphic['state'] = 'Image title not found'
         if not title: title = (img.title) or ("Image "+target)
         if not alt: alt = title
         if not longdesc: longdesc = title
         graphic['title'] = title
         tag = doTag(img,alt=alt,title=title,style=style,wap=wap,css_class=css_class,**kwargs).replace(request.BASE1,environment.relpath).strip()
         graphic['imgtag'] = tag
         graphic['tag'] = tag
         graphic['state'] = 'Absolute URL not found'
         url =  img.absolute_url().replace(request.BASE1,environment.relpath)
         graphic['imgurl'] = url
         graphic['url'] = url
         graphic['state'] = 'Image width not found'
         graphic['width'] = img.width
         graphic['state'] = 'Image width not found'
         graphic['height'] = img.height
         graphic['state'] = 'Image loaded successfully'
     except AttributeError:
         pass

     #debugging leak, January 05
     #be really sure that we don't leave references to acquired objects lying around
     if img is not None:
         del img
     if imgc is not None:
         del imgc

     if swftarget:
         graphic = flashOverride(here,swftarget,graphic)

     return graphic