\nOver the weekend I was writing some code in Google AppEngine and had a need to loop through all of the incoming request parameters so automatically update the contents of a model when there were request parameters which had the same name as the model attributes.<\/p>\n
\nWhen I wrote the very first version of the AE chapters for the class – I had this bit about dumping parameters in one chapter. In the rewrite to send the book to O’Reilly, I felt that this detail was too much so I cut it out about a month ago. I also cleaned up old copies of the chapter on my hard drive and on the appenginelearn.com site.<\/p>\n
\nSo on Saturday, I am sitting here peeved that I had this all figured out once and had even written it up once – exactly what I wanted – and then lost it.<\/p>\n
\nI figured that I had researched this once before – so I could figure it out again. I remember that there was no real documentation and I had to write stuff like dir() to hunt through methods. It was painful but I figured I could do it in an hour.<\/p>\n
\nSo I typed the following into Google:<\/p>\n
\nappengine looping through request variables<\/b><\/p>\n
\nI looked at the text of the second hit and it looked promising. Then I noticed the word “Michigan” in the text and then I noticed that it was *my chapter*. The lost chapter. So I clicked on the link (the PDF) and scrolled down and had my answer in about 45 seconds!<\/p>\n
\nI had forgotten to remove the copy on my Michigan personal AFS space – which I had used while teaching the class – Google had found it, indexed it and knew *somehow* that it was what I needed.<\/p>\n
\nSweet!<\/p>\n
<\/p>\n
\nHere is the code I used to loop throught the attributes from a request and update model values automatically:<\/p>\n
\n# Loop through the request keys and see if they can be put\n# into the model\ndef modelload(self, org, req, prefix = None):\nself.debug(\"ORM LOAD \"+str(org.__class__))\nfor key in req.params.keys():\nvalue = self.web.request.get(key)\nthetype = self.modeltype(org, key)\nif ( thetype == \"none\" and prefix != None ) :\nif ( not key.startswith(prefix) ) : continue\nkey = key[len(prefix):]\nthetype = self.modeltype(org, key)\nif ( thetype == \"none\" ) : continue\nself.debug(key+\" (\"+thetype+\") = \"+value)\nsetattr(org,key,value)\ndef modeltype(self, obj, key):\ntry:\nattr = str(type(getattr(obj.__class__, key)))\nexcept :\nreturn \"none\"\nif attr.find(\"ext.db.StringProperty\") > 0 : return \"string\"\nif attr.find(\"ext.db.ReferenceProperty\") > 0 : return \"reference\"\nif attr.find(\"ext.db.DateTimeProperty\") > 0: return \"datetime\"\nif attr.find(\"ext.db.IntegerProperty\") > 0: return \"int\"\nreturn \"none\"\n<\/pre>\nHere is the entire bit of code for folks who might be interested.<\/p>\n