view roundup/cgi/TAL/TALParser.py @ 5710:0b79bfcb3312

Add support for making an idempotent POST. This allows retrying a POST that was interrupted. It involves creating a post once only (poe) url /rest/data/<class>/@poe/<random_token>. This url acts the same as a post to /rest/data/<class>. However once the @poe url is used, it can't be used for a second POST. To make these changes: 1) Take the body of post_collection into a new post_collection_inner function. Have post_collection call post_collection_inner. 2) Add a handler for POST to rest/data/class/@poe. This will return a unique POE url. By default the url expires after 30 minutes. The POE random token is only good for a specific user and is stored in the session db. 3) Add a handler for POST to rest/data/<class>/@poe/<random token>. The random token generated in 2 is validated for proper class (if token is not generic) and proper user and must not have expired. If everything is valid, call post_collection_inner to process the input and generate the new entry. To make recognition of 2 stable (so it's not confused with rest/data/<:class_name>/<:item_id>), removed @ from Routing::url_to_regex. The current Routing.execute method stops on the first regular expression to match the URL. Since item_id doesn't accept a POST, I was getting 405 bad method sometimes. My guess is the order of the regular expressions is not stable, so sometime I would get the right regexp for /data/<class>/@poe and sometime I would get the one for /data/<class>/<item_id>. By removing the @ from the url_to_regexp, there was no way for the item_id case to match @poe. There are alternate fixes we may need to look at. If a regexp matches but the method does not, return to the regexp matching loop in execute() looking for another match. Only once every possible match has failed should the code return a 405 method failure. Another fix is to implement a more sophisticated mechanism so that @Routing.route("/data/<:class_name>/<:item_id>/<:attr_name>", 'PATCH') has different regexps for matching <:class_name> <:item_id> and <:attr_name>. Currently the regexp specified by url_to_regex is used for every component. Other fixes: Made failure to find any props in props_from_args return an empty dict rather than throwing an unhandled error. Make __init__ for SimulateFieldStorageFromJson handle an empty json doc. Useful for POSTing to rest/data/class/@poe with an empty document. Testing: added testPostPOE to test/rest_common.py that I think covers all the code that was added. Documentation: Add doc to rest.txt in the "Client API" section titled: Safely Re-sending POST". Move existing section "Adding new rest endpoints" in "Client API" to a new second level section called "Programming the REST API". Also a minor change to the simple rest client moving the header setting to continuation lines rather than showing one long line.
author John Rouillard <rouilj@ieee.org>
date Sun, 14 Apr 2019 21:07:11 -0400
parents 23b8e6067f7c
children
line wrap: on
line source

##############################################################################
#
# Copyright (c) 2001, 2002 Zope Corporation and Contributors.
# All Rights Reserved.
#
# This software is subject to the provisions of the Zope Public License,
# Version 2.0 (ZPL).  A copy of the ZPL should accompany this distribution.
# THIS SOFTWARE IS PROVIDED "AS IS" AND ANY AND ALL EXPRESS OR IMPLIED
# WARRANTIES ARE DISCLAIMED, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
# WARRANTIES OF TITLE, MERCHANTABILITY, AGAINST INFRINGEMENT, AND FITNESS
# FOR A PARTICULAR PURPOSE.
#
##############################################################################
"""
Parse XML and compile to TALInterpreter intermediate code.
"""

from .XMLParser import XMLParser
from .TALDefs import XML_NS, ZOPE_I18N_NS, ZOPE_METAL_NS, ZOPE_TAL_NS
from .TALGenerator import TALGenerator

class TALParser(XMLParser):

    ordered_attributes = 1

    def __init__(self, gen=None): # Override
        XMLParser.__init__(self)
        if gen is None:
            gen = TALGenerator()
        self.gen = gen
        self.nsStack = []
        self.nsDict = {XML_NS: 'xml'}
        self.nsNew = []

    def getCode(self):
        return self.gen.getCode()

    def getWarnings(self):
        return ()

    def StartNamespaceDeclHandler(self, prefix, uri):
        self.nsStack.append(self.nsDict.copy())
        self.nsDict[uri] = prefix
        self.nsNew.append((prefix, uri))

    def EndNamespaceDeclHandler(self, prefix):
        self.nsDict = self.nsStack.pop()

    def StartElementHandler(self, name, attrs):
        if self.ordered_attributes:
            # attrs is a list of alternating names and values
            attrlist = []
            for i in range(0, len(attrs), 2):
                key = attrs[i]
                value = attrs[i+1]
                attrlist.append((key, value))
        else:
            # attrs is a dict of {name: value}
            attrlist = sorted(attrs.items()) # Sorted for definiteness
        name, attrlist, taldict, metaldict, i18ndict \
              = self.process_ns(name, attrlist)
        attrlist = self.xmlnsattrs() + attrlist
        self.gen.emitStartElement(name, attrlist, taldict, metaldict, i18ndict)

    def process_ns(self, name, attrlist):
        taldict = {}
        metaldict = {}
        i18ndict = {}
        fixedattrlist = []
        name, namebase, namens = self.fixname(name)
        for key, value in attrlist:
            key, keybase, keyns = self.fixname(key)
            ns = keyns or namens # default to tag namespace
            item = key, value
            if ns == 'metal':
                metaldict[keybase] = value
                item = item + ("metal",)
            elif ns == 'tal':
                taldict[keybase] = value
                item = item + ("tal",)
            elif ns == 'i18n':
                assert 0, "dealing with i18n: " + repr((keybase, value))
                i18ndict[keybase] = value
                item = item + ('i18n',)
            fixedattrlist.append(item)
        if namens in ('metal', 'tal', 'i18n'):
            taldict['tal tag'] = namens
        return name, fixedattrlist, taldict, metaldict, i18ndict

    def xmlnsattrs(self):
        newlist = []
        for prefix, uri in self.nsNew:
            if prefix:
                key = "xmlns:" + prefix
            else:
                key = "xmlns"
            if uri in (ZOPE_METAL_NS, ZOPE_TAL_NS, ZOPE_I18N_NS):
                item = (key, uri, "xmlns")
            else:
                item = (key, uri)
            newlist.append(item)
        self.nsNew = []
        return newlist

    def fixname(self, name):
        if ' ' in name:
            uri, name = name.split(' ')
            prefix = self.nsDict[uri]
            prefixed = name
            if prefix:
                prefixed = "%s:%s" % (prefix, name)
            ns = 'x'
            if uri == ZOPE_TAL_NS:
                ns = 'tal'
            elif uri == ZOPE_METAL_NS:
                ns = 'metal'
            elif uri == ZOPE_I18N_NS:
                ns = 'i18n'
            return (prefixed, name, ns)
        return (name, name, None)

    def EndElementHandler(self, name):
        name = self.fixname(name)[0]
        self.gen.emitEndElement(name)

    def DefaultHandler(self, text):
        self.gen.emitRawText(text)

def test():
    import sys
    p = TALParser()
    file = "tests/input/test01.xml"
    if sys.argv[1:]:
        file = sys.argv[1]
    p.parseFile(file)
    program, macros = p.getCode()
    from .TALInterpreter import TALInterpreter
    from .DummyEngine import DummyEngine
    engine = DummyEngine(macros)
    TALInterpreter(program, macros, engine, sys.stdout, wrap=0)()

if __name__ == "__main__":
    test()

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