Background: I'm new to html and fastAPI and not sure about the right terminology for the questions I have. I know how to insert a image in html by doing following:
<img scr="create_image" alt="">
and then on python side I can write something like below to create and insert the image
#app.route("/create_image")
def image():
# create a image
return image
Question: I'm trying to do something similar for insert a table into html but not sure what code to write on the html end, but something similar like below
<table scr="create_table" alt=""> # its definitely wrong, but this is the idea.
on the python side, I'm planning to do following:
#app.route("/create_table")
def table():
df = pd.DataFrame({"col1":[1,2],"col2":[3,4]})
return df.to_html()
the following code in html file will serve the purpose
<iframe src="create_table"></iframe>
So what I am trying to achieve is really simple.
I want to call python test.py and would like to go to my local host and see the html result. However I keep getting an error ValueError: Invalid tag name u'<html><body><h1>Test!</h1></body></html>'
Below is my code. What's the problem here?
import lxml.etree as ETO
html = ETO.Element("<html><body><h1>Test!</h1></body></html>")
self.wfile.write(ETO.tostring(html, xml_declaration=False, pretty_print=True))
You have to create each element in turn, and put them in the structure that you want them to have:
html = ETO.Element('html')
body = ETO.SubElement(html, 'body')
h1 = ETO.SubElement(body, 'h1')
h1.text = 'Test!'
Then ETO.tostring(html) will return a bytestring that looks like this:
>>> ETO.tostring(html)
b'<html><body><h1>Test!</h1></body></html>'
Since you are reading an existing file, Element isn't useful here; try changing this
html = ETO.Element("<html><body><h1>Test!</h1></body></html>")
to this
html = ETO.fromstring("<html><body><h1>Test!</h1></body></html>")
and see if it works for you.
I have flask, jinja2 and python.
So, I'm trying to display text that is stored as markdown.
I do this
class Article(db.Entity):
...
def html(self):
return markdown(self.text) # from markdown import markdown
Next in my view I do this
html_text = article_.html()
return render_template('article.html', article=article_, comments=comments, user=user, text=html_text)
And in article.html I just have this line
{{text}}
So, with data stored in db as *im busy* I have <p><em>im busy</em></p> in my browser.
I tried to use .replace('<', '<').replace('>', '>') but it changes nothing.
Do you know safe filter?
{{text|safe}}
Passing HTML to template using Flask/Jinja2
Im trying to display the content of a text file in a template without any luck so far. This is
my code so far:
#route('/show_article/<filename>')
def show_article(filename):
stat_art=static_file(filename, root="articles")
return template('show_article', stat_art=stat_art)
And this is the paragraph in my template to display the content of the file
<p>
{{stat_art}}
</p>
I know that I could just return the static_file() but I will need to design the page with
some css and stuff later.
Thanks in advance and sorry for if my english is not correct!
You've misunderstood what static_file does.
Luckily, the fix is simple: just read the file yourself and pass its contents to the template, like so:
#route('/show_article/<filename>')
def show_article(filename):
with open(filename) as f: # <-- you'll need the correct path here, possibly including "articles"
stat_art = f.read()
return template('show_article', stat_art=stat_art)
That should do the trick.
[Btw, nice first question!]
In python, what is the most elegant way to generate HTML documents. I currently manually append all of the tags to a giant string, and write that to a file. Is there a more elegant way of doing this?
You can use yattag to do this in an elegant way. FYI I'm the author of the library.
from yattag import Doc
doc, tag, text = Doc().tagtext()
with tag('html'):
with tag('body'):
with tag('p', id = 'main'):
text('some text')
with tag('a', href='/my-url'):
text('some link')
result = doc.getvalue()
It reads like html, with the added benefit that you don't have to close tags.
I would suggest using one of the many template languages available for python, for example the one built into Django (you don't have to use the rest of Django to use its templating engine) - a google query should give you plenty of other alternative template implementations.
I find that learning a template library helps in so many ways - whenever you need to generate an e-mail, HTML page, text file or similar, you just write a template, load it with your template library, then let the template code create the finished product.
Here's some simple code to get you started:
#!/usr/bin/env python
from django.template import Template, Context
from django.conf import settings
settings.configure() # We have to do this to use django templates standalone - see
# http://stackoverflow.com/questions/98135/how-do-i-use-django-templates-without-the-rest-of-django
# Our template. Could just as easily be stored in a separate file
template = """
<html>
<head>
<title>Template {{ title }}</title>
</head>
<body>
Body with {{ mystring }}.
</body>
</html>
"""
t = Template(template)
c = Context({"title": "title from code",
"mystring":"string from code"})
print t.render(c)
It's even simpler if you have templates on disk - check out the render_to_string function for django 1.7 that can load templates from disk from a predefined list of search paths, fill with data from a dictory and render to a string - all in one function call. (removed from django 1.8 on, see Engine.from_string for comparable action)
If you're building HTML documents than I highly suggest using a template system (like jinja2) as others have suggested. If you're in need of some low level generation of html bits (perhaps as an input to one of your templates), then the xml.etree package is a standard python package and might fit the bill nicely.
import sys
from xml.etree import ElementTree as ET
html = ET.Element('html')
body = ET.Element('body')
html.append(body)
div = ET.Element('div', attrib={'class': 'foo'})
body.append(div)
span = ET.Element('span', attrib={'class': 'bar'})
div.append(span)
span.text = "Hello World"
if sys.version_info < (3, 0, 0):
# python 2
ET.ElementTree(html).write(sys.stdout, encoding='utf-8',
method='html')
else:
# python 3
ET.ElementTree(html).write(sys.stdout, encoding='unicode',
method='html')
Prints the following:
<html><body><div class="foo"><span class="bar">Hello World</span></div></body></html>
There is also a nice, modern alternative: airium: https://pypi.org/project/airium/
from airium import Airium
a = Airium()
a('<!DOCTYPE html>')
with a.html(lang="pl"):
with a.head():
a.meta(charset="utf-8")
a.title(_t="Airium example")
with a.body():
with a.h3(id="id23409231", klass='main_header'):
a("Hello World.")
html = str(a) # casting to string extracts the value
print(html)
Prints such a string:
<!DOCTYPE html>
<html lang="pl">
<head>
<meta charset="utf-8" />
<title>Airium example</title>
</head>
<body>
<h3 id="id23409231" class="main_header">
Hello World.
</h3>
</body>
</html>
The greatest advantage of airium is - it has also a reverse translator, that builds python code out of html string. If you wonder how to implement a given html snippet - the translator gives you the answer right away.
Its repository contains tests with example pages translated automatically with airium in: tests/documents. A good starting point (any existing tutorial) - is this one: tests/documents/w3_architects_example_original.html.py
I would recommend using xml.dom to do this.
http://docs.python.org/library/xml.dom.html
Read this manual page, it has methods for building up XML (and therefore XHTML). It makes all XML tasks far easier, including adding child nodes, document types, adding attributes, creating texts nodes. This should be able to assist you in the vast majority of things you will do to create HTML.
It is also very useful for analysing and processing existing xml documents.
Here is a tutorial that should help you with applying the syntax:
http://www.postneo.com/projects/pyxml/
I am using the code snippet known as throw_out_your_templates for some of my own projects:
https://github.com/tavisrudd/throw_out_your_templates
https://bitbucket.org/tavisrudd/throw-out-your-templates/src
Unfortunately, there is no pypi package for it and it's not part of any distribution as this is only meant as a proof-of-concept. I was also not able to find somebody who took the code and started maintaining it as an actual project. Nevertheless, I think it is worth a try even if it means that you have to ship your own copy of throw_out_your_templates.py with your code.
Similar to the suggestion to use yattag by John Smith Optional, this module does not require you to learn any templating language and also makes sure that you never forget to close tags or quote special characters. Everything stays written in Python. Here is an example of how to use it:
html(lang='en')[
head[title['An example'], meta(charset='UTF-8')],
body(onload='func_with_esc_args(1, "bar")')[
div['Escaped chars: ', '< ', u'>', '&'],
script(type='text/javascript')[
'var lt_not_escaped = (1 < 2);',
'\nvar escaped_cdata_close = "]]>";',
'\nvar unescaped_ampersand = "&";'
],
Comment('''
not escaped "< & >"
escaped: "-->"
'''),
div['some encoded bytes and the equivalent unicode:',
'你好', unicode('你好', 'utf-8')],
safe_unicode('<b>My surrounding b tags are not escaped</b>'),
]
]
I am attempting to make an easier solution called
PyperText
In Which you can do stuff like this:
from PyperText.html import Script
from PyperText.htmlButton import Button
#from PyperText.html{WIDGET} import WIDGET; ex from PyperText.htmlEntry import Entry; variations shared in file
myScript=Script("myfile.html")
myButton=Button()
myButton.setText("This is a button")
myScript.addWidget(myButton)
myScript.createAndWrite()
I wrote a simple wrapper for the lxml module (should work fine with xml as well) that makes tags for HTML/XML -esq documents.
Really, I liked the format of the answer by John Smith but I didn't want to install yet another module to accomplishing something that seemed so simple.
Example first, then the wrapper.
Example
from Tag import Tag
with Tag('html') as html:
with Tag('body'):
with Tag('div'):
with Tag('span', attrib={'id': 'foo'}) as span:
span.text = 'Hello, world!'
with Tag('span', attrib={'id': 'bar'}) as span:
span.text = 'This was an example!'
html.write('test_html.html')
Output:
<html><body><div><span id="foo">Hello, world!</span><span id="bar">This was an example!</span></div></body></html>
Output after some manual formatting:
<html>
<body>
<div>
<span id="foo">Hello, world!</span>
<span id="bar">This was an example!</span>
</div>
</body>
</html>
Wrapper
from dataclasses import dataclass, field
from lxml import etree
PARENT_TAG = None
#dataclass
class Tag:
tag: str
attrib: dict = field(default_factory=dict)
parent: object = None
_text: str = None
#property
def text(self):
return self._text
#text.setter
def text(self, value):
self._text = value
self.element.text = value
def __post_init__(self):
self._make_element()
self._append_to_parent()
def write(self, filename):
etree.ElementTree(self.element).write(filename)
def _make_element(self):
self.element = etree.Element(self.tag, attrib=self.attrib)
def _append_to_parent(self):
if self.parent is not None:
self.parent.element.append(self.element)
def __enter__(self):
global PARENT_TAG
if PARENT_TAG is not None:
self.parent = PARENT_TAG
self._append_to_parent()
PARENT_TAG = self
return self
def __exit__(self, typ, value, traceback):
global PARENT_TAG
if PARENT_TAG is self:
PARENT_TAG = self.parent