 | ClientFormClient-side HTML form handling. |
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ClientForm Description
Client-side HTML form handling. ClientForm is a Python module for handling HTML forms on the client side, useful for parsing HTML forms, filling them in and returning the completed forms to the server. ClientForm was developed from a port of Gisle Aas' Perl module HTML::Form, from the libwww-perl library, but the interface is not the same.Simple working example:from urllib2 import urlopenfrom ClientForm import ParseResponseresponse = urlopen("")forms = ParseResponse(response, backwards_compat=False)form = formsprint formform = "Thanks, Gisle"# form.click() returns a urllib2.Request object# (see HTMLForm.click.__doc__ if you don't have urllib2)print urlopen(form.click()).read()A more complicated working example (Note: this example makes use of the ClientForm 0.2 API; refer to the README.html file in the latest 0.1 release for the corresponding code for that version.):import ClientFormimport urllib2request = urllib2.Request( "")response = urllib2.urlopen(request)forms = ClientForm.ParseResponse(response, backwards_compat=False)response.close()## f = open("example.html")## forms = ClientForm.ParseFile(f, "http://example.com/example.html",## backwards_compat=False)## f.close()form = formsprint form # very useful!# A 'control' is a graphical HTML form widget: a text entry box, a# dropdown 'select' list, a checkbox, etc.# Indexing allows setting and retrieval of control valuesoriginal_text = form # a string, NOT a Control instanceform = "Blah."# Controls that represent lists (checkbox, select and radio lists) are# ListControl instances. Their values are sequences of list item names.# They come in two flavours: single- and multiple-selection:form = # singleform = # multi# equivalent, but more flexible:form.set_value(, name="cheeses")# Add files to FILE controls with .add_file(). Only call this multiple# times if the server is expecting multiple files.# add a file, default value for MIME type, no filename sent to serverform.add_file(open("data.dat"))# add a second file, explicitly giving MIME type, and telling the server# what the filename isform.add_file(open("data.txt"), "text/plain", "data.txt")# All Controls may be disabled (equivalent of greyed-out in browser)...control = form.find_control("comments")print control.disabled# ...or readonlyprint control.readonly# readonly and disabled attributes can be assigned tocontrol.disabled = False# convenience method, used here to make all controls writable (unless# they're disabled):form.set_all_readonly(False)# A couple of notes about list controls and HTML:# 1. List controls correspond to either a single SELECT element, or# multiple INPUT elements. Items correspond to either OPTION or INPUT# elements. For example, this is a SELECT control, named "control1":# < select name="control1" ># < option >foo< /option ># < option value="1" >bar< /option ># < /select ># and this is a CHECKBOX control, named "control2":# < input type="checkbox" name="control2" value="foo" id="cbe1" ># < input type="checkbox" name="control2" value="bar" id="cbe2" ># You know the latter is a single control because all the name attributes# are the same.# 2. Item names are the strings that go to make up the value that should# be returned to the server. These strings come from various different# pieces of text in the HTML. The HTML standard and the ClientForm# docstrings explain in detail, but playing around with an HTML file,# ParseFile() and 'print form' is very useful to understand this!# You can get the Control instances from inside the form...control = form.find_control("cheeses", type="select")print control.name, control.value, control.typecontrol.value = # ...and the Item instances from inside the Controlitem = control.get("curd")print item.name, item.selected, item.id, item.attrsitem.selected = False# Controls may be referred to by label:# find control with label that has a *substring* "Cheeses"# (eg., a label "Please select a cheese" would match).control = form.find_control(label="select a cheese")# You can explicitly say that you're referring to a ListControl:# set value of "cheeses" ListControlform.set_value(, name="cheeses", kind="list")# equivalent:form.find_control(name="cheeses", kind="list").value = # the first example is also almost equivalent to the following (but# insists that the control be a ListControl -- so it will skip any# non-list controls that come before the control we want)form = # The kind argument can also take values "multilist", "singlelist", "text",# "clickable" and "file":# find first control that will accept text, and scribble in itform.set_value("rhubarb rhubarb", kind="text", nr=0)# find, and set the value of, the first single-selection list controlform.set_value(, kind="singlelist", nr=0)# You can find controls with a general predicate function:def control_has_caerphilly(control): for item in control.items: if item.name == "caerphilly": return Trueform.find_control(kind="list", predicate=control_has_caerphilly)# HTMLForm.controls is a list of all controls in the formfor control in form.controls: if control.value == "inquisition": sys.exit()# Control.items is a list of all Item instances in the controlfor item in form.find_control("cheeses").items: print item.name# To remove items from a list control, remove it from .items:cheeses = form.find_control("cheeses")curd = cheeses.get("curd")del cheeses.items# To add items to a list container, instantiate an Item with its control# and attributes:# Note that you are responsible for getting the attributes correct here,# and these are not quite identical to the original HTML, due to# defaulting rules and a few special attributes (e.g. Items that represent# OPTIONs have a special "contents" key in their .attrs dict). In future# there will be an explicitly supported way of using the parsing logic to# add items and controls from HTML strings without knowing these details.ClientForm.Item(cheeses, {"contents": "mascarpone", "value": "mascarpone"})# You can specify list items by label using set/get_value_by_label() and# the label argument of the .get() method. Sometimes labels are easier to# maintain than names, sometimes the other way around.form.set_value_by_label(, "cheeses")# Which items are present, selected, and successful?# is the "parmesan" item of the "cheeses" control successful (selected# and not disabled)?print "parmesan" in form# is the "parmesan" item of the "cheeses" control selected?print "parmesan" in # does cheeses control have a "caerphilly" item?print "caerphilly" in # Sometimes one wants to set or clear individual items in a list, rather# than setting the whole .value:# select the item named "gorgonzola" in the first control named "cheeses"form.find_control("cheeses").get("gorgonzola").selected = True# You can be more specific:# deselect "edam" in third CHECKBOX controlform.find_control(type="checkbox", nr=2).get("edam").selected = False# deselect item labelled "Mozzarella" in control with id "chz"form.find_control(id="chz").get(label="Mozzarella").selected = False# Often, a single checkbox (a CHECKBOX control with a single item) is# present. In that case, the name of the single item isn't of much# interest, so it's a good idea to check and uncheck the box without# using the item name:form.find_control("smelly").items.selected = True # checkform.find_control("smelly").items.selected = False # uncheck# Items may be disabled (selecting or de-selecting a disabled item is# not allowed):control = form.find_control("cheeses")print control.get("emmenthal").disabledcontrol.get("emmenthal").disabled = True# enable all items in controlcontrol.set_all_items_disabled(False)request2 = form.click() # urllib2.Request objecttry: response2 = urllib2.urlopen(request2)except urllib2.HTTPError, response2: passprint response2.geturl()print response2.info() # headersprint response2.read() # bodyresponse2.close()All of the standard control types are supported: TEXT, PASSWORD, HIDDEN, TEXTAREA, ISINDEX, RESET, BUTTON (INPUT TYPE=BUTTON and the various BUTTON types), SUBMIT, IMAGE, RADIO, CHECKBOX, SELECT/OPTION and FILE (for file upload). Both standard form encodings (application/x-www-form-urlencoded and multipart/form-data) are supported.The module is designed for testing and automation of web interfaces, not for implementing interactive user agents.Security note: Remember that any passwords you store in HTMLForm instances will be saved to disk in the clear if you pickle them (directly or indirectly). The simplest solution to this is to avoid pickling HTMLForm objects. You could also pickle before filling in any password, or just set the password to "" before pickling. Requirements: · Python
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