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Using action requests¶
The traditional variable name for action requests in application code and method
signatures is ar. Except for the plain BaseRequest instance returned by
rt.login, which is sometimes called ses because
you can imagine it as a session.
As a rough approximation you can say that every incoming web request gets wrapped into an action request. The ActionRequest adds some more information about the context (like the “renderer” being used) and provides methods for communicating with the user.
But there are exceptions to this approximaton.
showset_responselino.core.request.get_permission()lino.core.request.set_action_param_values()lino.core.request.ar2button()
Iterating over table requests
A table request has two iterators: data_iterator and
sliced_data_iterator.
>>> from lino_book.projects.min1.startup import *
>>> rt.show('countries.Places', limit=10)
============ ======================== ================== ================== ============ ========== ================================
Country Designation Designation (de) Designation (fr) Place Type zip code Part of
------------ ------------------------ ------------------ ------------------ ------------ ---------- --------------------------------
Bangladesh Cumilla City
Bangladesh Dhaka City
Belgium Aalst Aalst Alost City 9300 Flandre de l'Est / Ostflandern
Belgium Aalst-bij-Sint-Truiden Village 3800 Limbourg / Limburg
Belgium Angleur City 4031
Belgium Ans City 4430
Belgium Anvers Antwerpen Anvers Province
Belgium Baardegem Village 9310 9300 Aalst / Alost
Belgium Baelen Baelen Baelen City 4837 Liège / Lüttich
Belgium Blégny City 4670
============ ======================== ================== ================== ============ ========== ================================
>>> rt.show('countries.Places', offset=5, limit=3)
========= ============= ================== ================== ============ ========== ====================
Country Designation Designation (de) Designation (fr) Place Type zip code Part of
--------- ------------- ------------------ ------------------ ------------ ---------- --------------------
Belgium Ans City 4430
Belgium Anvers Antwerpen Anvers Province
Belgium Baardegem Village 9310 9300 Aalst / Alost
========= ============= ================== ================== ============ ========== ====================
>>> rt.show('countries.Places', offset=-5, limit=3)
Traceback (most recent call last):
...
ValueError: Negative indexing is not supported.
>>> ar = countries.Places.create_request(offset=5, limit=3)
>>> print(' '.join([pl.name for pl in ar]))
Cumilla Dhaka Aalst Aalst-bij-Sint-Truiden Angleur Ans Anvers Baardegem Baelen Blégny Brabant flamant Brabant wallon Brussels Burdinne Burg-Reuland Butgenbach Büllingen Cerfontaine Cuesmes Erembodegem Eupen Flandre de l'Est Flandre de l'Ouest Gijzegem Hainaut Herdersem Hofstade Kelmis Kettenis La Reid Limbourg Liège Liège Luxembourg Meldert Mons Moorsel Mortier Namur Namur Nieuwerkerken Nispert Ostende Ottignies Ouren Raeren Recht Sankt Vith Thieusies Trembleur Aachen Berlin Cologne Hamburg Monschau Munich Harju Kesklinn Narva Pärnu Pärnu Põhja-Tallinn Rapla Rapla Tallinn Tartu Vigala Ääsmäe Marseille Metz Nancy Nice Paris Strasbourg Amsterdam Breda Den Haag Maastricht Rotterdam Utrecht
>>> print(' '.join([pl.name for pl in ar.sliced_data_iterator]))
Ans Anvers Baardegem
(TODO: write much more text. we would need a good explanation of how to create subrequests etc.)
Pointing to a database object¶
Every database object (in Lino) has a method as_summary_item, which you can call to generate a HTML tree
element that is going to output a <a href> tag. (Read more about where you
need them in Generating HTML.)
>>> ar = rt.login('robin')
>>> obj = contacts.Person.objects.get(pk=51)
>>> def example(x):
... print(tostring(x))
Basic usage is:
>>> example(ar.obj2html(obj))
<a href="…">Mr Erwin Emontspool</a>
When you don’t specify a text for the link, obj2html calls the object’s
__str__() method and use the result as text. You can specify your own
text by giving a second positional argument:
>>> example(ar.obj2html(obj, "Foo"))
<a href="…">Foo</a>
Note
The URL (”…” in above examples) is something you aren’t supposed to worry
about as an application developer. It depends on the front
end, which is known to the action request as renderer. In a tested
document the default renderer is a
lino.core.renderer.TextRenderer, which uses these fake URLs “…”. If
you manuall set a real renderer, you’ll get real URLs.
>>> ar.renderer
<lino.core.renderer.TextRenderer object at ...>
>>> real_renderer = settings.SITE.kernel.default_renderer
>>> real_renderer
<lino.modlib.extjs.ext_renderer.ExtRenderer object at ...>
>>> ar2 = rt.login("robin", renderer=real_renderer)
>>> example(ar2.obj2html(obj))
<a href="javascript:Lino.contacts.Persons.detail.run(null,{ "record_id": 51 })" style="text-decoration:none">Mr Erwin Emontspool</a>
For the remaining examples in this document we use the text renderer.
Your text should usually be a translatable string:
>>> from lino.ad import _
>>> with translation.override("de"):
... example(ar.obj2html(obj, _("Today")))
<a href="…">Heute</a>
Your text will be escaped:
>>> example(ar.obj2html(obj, "Foo & bar"))
<a href="…">Foo & bar</a>
That’s why the following does not yield the expected result:
>>> example(ar.obj2html(obj, "<img src=\"foo\"/>"))
<a href="…"><img src="foo"/></a>
In above situation you can specify another HTML tree element as “text”. Here is what you expected:
>>> example(ar.obj2html(obj, E.img(src="foo")))
<a href="…"><img src="foo"/></a>
You can also specify a tuple with text chunks:
>>> text = ("Formatted ", E.b("rich"), " text")
>>> example(ar.obj2html(obj, text))
<a href="…">Formatted <b>rich</b> text</a>
If you want your text to be that of another database object, then you
must explicitly call that object’s __str__() method:
>>> other = contacts.Person.objects.get(pk=52)
>>> example(ar.obj2html(obj, str(other)))
<a href="…">Mrs Erna Emonts-Gast</a>
More examples:
>>> with translation.override("de"):
... example(ar.obj2html(obj, (_("Monday"), " & ", _("Tuesday"))))
<a href="…">Montag & Dienstag</a>
The summary display mode¶
Programmatically doing requests¶
>>> u = rt.models.users.User.objects.get(username="robin")
>>> r = rt.models.contacts.Persons.request(
... user=u, renderer=dd.plugins.extjs.renderer)
>>> print(r.renderer.request_handler(r))
Lino.contacts.Persons.grid.run(null,{ "base_params": { }, "param_values": { "end_date": null, "observed_event": null, "start_date": null } })