README Copy Section

Welcome to Helium's documentation

The documentation is built using
sphinx and the theme used is
sphinx-rtd-theme.

Setting up documentation locally Copy Chapter

Ensure you have python and pip installed on your
system and then run this command in the project root:

pip install -Ur requirements/docs.txt
make -C docs/ html

This will install all development dependencies for the project and then build
the documentation in HTML format in docs/_build/ directory. Open
docs/_build/index.html in your browser to see the documentation.

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Cheatsheet Copy Section

Helium cheatsheet

This page very quickly teaches you the most important parts of Helium's API.

Importing Copy Chapter

All of Helium's public functions lie directly in the module helium.
You can for instance import them as follows:

from helium import *

Starting a browser Copy Chapter

Helium currently supports Chrome and Firefox. You can start them with the
following functions:

start_chrome()
start_firefox()

You can optionally pass a URL to open (eg. start_chrome('google.com'))

Headless browser Copy Chapter

When you type the above commands, you will actually see a browser window open.
This is useful for developing your scripts. However, once you run them, you may
not want this window to appear. You can achieve this by adding headless=True:

start_chrome(headless=True)
start_chrome('google.com', headless=True)

(Similarly for start_firefox(...) of course.)

Interacting with a web site Copy Chapter

The following example shows the most typical statements in a Helium script:

from helium import *
start_chrome('google.com')
write('helium selenium github')
press(ENTER)
click('mherrmann/helium')
go_to('github.com/login')
write('username', into='Username')
write('password', into='Password')
click('Sign in')
kill_browser()

Most of your own code will (hopefully) be as simple as the above.

Element types Copy Chapter

The above example used pure strings such as Sign in to identify elements on
the web page. But Helium also lets you target elements more specifically.
For instance:

* Link('Sign in')
* Button('Sign in')
* TextField('First name')
* CheckBox('I accept')
* RadioButton('Windows')
* Image(alt='Helium logo')

You can pass them into other functions such as click(Link('Sign in')).
But you can also use them to _read_ data from the web site. For instance:

print(TextField('First name').value)

A common use case is to use .exists() to check for the existence of an
element. For example:

if Text('Accept cookies?').exists():
    click('I accept')

I also often find Text(...).value useful for reading out data:

name = Text(to_right_of='Name:', below=Image(alt='Profile picture')).value

For a full list of element types and their properties, please see
the source code.

Finding elements relative to others Copy Chapter

You already saw in the previous section how above=... and to_right_of=...
let you find elements relative to other elements. You can similarly use
below=... and to_left_of. Here are some more examples.

Text(above='Balance', below='Transactions').value
Link(to_right_of='Invoice:')
Image(to_right_of=Link('Sign in', below=Text('Navigation')))

Waiting for elements to appear (or other conditions) Copy Chapter

Use
wait_until(...)
to wait for a condition to become true. For example:

wait_until(Button('Download').exists)

But you can also use this to wait for an arbitrary condition:

wait_until(lambda: TextField('Balance').value == '$2M')

jQuery-style selectors Copy Chapter

Sometimes, you do need to fall back to using HTML IDs, CSS Selectors or XPaths
to identify an element on the web page. Helium's
S(...)
predicate lets you do this. The parameter you pass to it is interpreted as
follows:

* If it starts with an `@, then it identifies elements by HTML name.
Eg. S("@btnName") identifies an element with name="btnName".
* If it starts with //, then Helium interprets it as an XPath.
* Otherwise, Helium interprets it as a CSS selector. This in particular
lets you write S("#myId") to identify an element with id="myId",
or S(".myClass") to identify elements with class="myClass".

As before, you can combine S(...) with other functions such as
click(S(...)), or use it to extract data. For an example of this, see
below.

Combining Helium and Selenium's APIs Copy Chapter

All Helium does is translate your high-level commands into low-level Selenium
function calls. Because of this, you can freely mix Selenium and Helium. For
example:

A Helium function:

driver = start_chrome()
A Selenium API:

driver.execute_script("alert('Hi!');")

You can also get / set the Selenium WebDriver which Helium uses via
get_driver()
and
set_driver(...).

With the WebDriver instance, you can execute any Selenium commands you want.

To use Helium's API's to obtain Selenium WebElements, use the .web_element
property of Helium's various GUI elements. For instance:

Get the CSS class of the "Helium" link:

Link('Helium').web_element.get_attribute('class')

Here, .get_attribute(...) is a Selenium API.

Finding all elements Copy Chapter

The .web_element property and the S(...) predicate are particularly useful
for extracting multiple pieces of data from a web page. To do this, you can use
Helium's find_all(...) function.
As its name implies, it lets you find all occurrences of an element on a page.
For example:

email_cells = find_all(S("table > tr > td", below="Email"))
emails = [cell.web_element.text for cell in email_cells]

Implicit waits Copy Chapter

When you issue a command such as click('Download'), Helium by default waits
up to 10 seconds for the respective element to appear. This feature is called
"implicit waiting". You can change the 10 second default to a different value
via the
Config class:

Config.implicit_wait_secs = 30

However, before you do this, it may be better to add explicit waits to your
code, such as wait_until(Button('Download').exists).

Alerts Copy Chapter

The
Alert class
lets you interface with JavaScript popup boxes. Use Alert().accept(),
Alert().dismiss() to click "Ok" or "Cancel", Alert().text to read the
message shown, or write(..., into=Alert()) to enter a value.

File uploads, drag and drop, combo boxes, popups Copy Chapter

Use
attach_file(...),
drag_file(...),
drag(...),
select(...),
switch_to(...).

Clicking at x, y coordinates Copy Chapter

Sometimes, you may want to click at a specific (x, y) coordinate, or at an
offset of an element.

Create a Point to specify the coordinates and use it to click: to specify the coordinates and use it to click:')" title="Copy section prompt for LLMs"> Copy Section

from helium import click
point = Point(x=100, y=200)
click(point)  # Clicks at (100, 200)

Adjusting a Point by a offset Copy Section

delta = (20, -10)
click(Point(100, 200) + delta)  # Clicks at (120, 190)

See the
Point class
for more.

Taking a screenshot Copy Chapter

Use Selenium's API:

get_driver().save_screenshot(r'C:\screenshot.png')

Note the leading r. This is required because the string contains a backslash
\.

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Contributors Copy Section

Contributors to this project
============================
..
Please use this format to add your contributions to this file
SocialUsernameName <Profile-Url>_ (Your Name) - Description of your contribution in a few words

- mherrmann <https://github.com/mherrmann>_ (Michael Herrmann) - Project creator and maintainer
- IgnisDa <https://github.com/IgnisDa>_ (Diptesh Choudhuri) - Documentation maintainer

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Index Copy Section

Welcome to Helium's documentation!
==================================

Helium is a Python library for automating web sites. It is based on
Selenium-python <https://selenium-python.readthedocs.io/>_.
Selenium is great, but difficult to use. Helium wraps around Selenium to give
you a simpler API. Helium's name comes from being a lighter chemical element
than Selenium.

For a quick overview of Helium's features, please see
the project home page <https://github.com/mherrmann/helium>_.
Here, in the documentation, you will find a more comprehensive reference.


.. toctree::
:maxdepth: 2
:caption: Contents:

installation.rst
api.rst
contributors.rst

Indices and tables
==================

* :ref:genindex
* :ref:search

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Installation Copy Section

Installation
============

To install Helium, you need Python 3 and Chrome or Firefox.

If you already know Python, then the following command should be all you need:


.. code-block:: bash

pip install helium

Otherwise - Hi! I would recommend you create a virtual environment in the
current directory. Any libraries you download (such as Helium) will be placed
there. Enter the following into a command prompt:

.. code-block:: bash

python3 -m venv venv

This creates a virtual environment in the venv/ directory. To activate it:

.. code-block:: bash

# On Mac/Linux, bash shell:
source venv/bin/activate
# On Windows:
call venv\Scripts\activate.bat

Then, install Helium using pip:

.. code-block:: bash

python -m pip install helium

Now enter :code:python into the command prompt and the command :code:from
helium import * and you are ready to get started!

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README Copy Section

Lighter web automation with Python

Helium is a Python library for automating browsers such as Chrome and Firefox.
For example:

Installation Copy Chapter

To get started with Helium, you need Python 3 and Chrome or Firefox.

I would recommend creating a virtual environment. This lets you install Helium
for just your current project, instead of globally on your whole computer.

To create and activate a virtual environment, type the following commands into
a command prompt window:

python3 -m venv venv
On Mac/Linux:

source venv/bin/activate
On Windows:

call venv\scripts\activate.bat

python -m pip install helium

Now enter python into the command prompt and (for instance) the commands in
the animation at the top of this page (from helium import *, ...).

Your first script Copy Chapter

I've compiled a cheatsheet that quickly teaches you all
you need to know to be productive with Helium. For a more complete reference of
Helium's features, please see the
documentation.

Connection to Selenium Copy Chapter

Under the hood, Helium forwards each call to Selenium. The difference is that
Helium's API is much more high-level. In Selenium, you need to use HTML IDs,
XPaths and CSS selectors to identify web page elements. Helium on the other hand
lets you refer to elements by user-visible labels. As a result, Helium scripts
are typically 30-50% shorter than similar Selenium scripts. What's more, they
are easier to read and more stable with respect to changes in the underlying web
page.

Because Helium is simply a wrapper around Selenium, you can freely mix the two
libraries. For example:

A Helium function:

driver = start_chrome()
A Selenium API:

driver.execute_script("alert('Hi!');")

So in other words, you don't lose anything by using Helium over pure Selenium.

In addition to its more high-level API, Helium simplifies further tasks that are
traditionally painful in Selenium:

- iFrames: Unlike Selenium, Helium lets you interact with elements inside
nested iFrames, without having to first "switch to" the iFrame.
- Window management. Helium notices when popups open or close and focuses /
defocuses them like a user would. You can also easily switch to a window by
(parts of) its title. No more having to iterate over Selenium window handles.
- Implicit waits. By default, if you try click on an element with Selenium
and that element is not yet present on the page, your script fails. Helium by
default waits up to 10 seconds for the element to appear.
- Explicit waits. Helium gives you a much nicer API for waiting for a
condition on the web page to become true. For example: To wait for an element
to appear in Selenium, you would write:


element = WebDriverWait(driver, 10).until(
      EC.presence_of_element_located((By.ID, "myDynamicElement"))
  )

wait_until(Button('Download').exists)

pip install -Ur requirements/test.txt
python setup.py test

This runs the tests against Chrome. To run them against Firefox, set the
environment variable TEST_BROWSER to firefox. Eg. on Mac/Linux:

TEST_BROWSER=firefox python setup.py test

On Windows:

set TEST_BROWSER=firefox
python setup.py test

If you do add new functionality, you should also add tests for it. Please see
the tests/` directory for what this might look like.

History Copy Chapter

I (Michael Herrmann) originally developed Helium in 2013 for a Polish IT startup
called BugFree software. (It could be that you have seen Helium before at
https://heliumhq.com.) We shut down the company at the end of 2019 and I felt it
would be a shame if Helium simply disappeared from the face of the earth. So I
invested some time to modernize it and bring it into a state suitable for open
source.

Helium used to be available for both Java and Python. But because I now only
use it from Python, I didn't have time to bring the Java implementation up to
speed as well. Similarly for Internet Explorer: Helium used to support it, but
since I have no need for it, I removed the (probably broken) old implementation.

The name Helium was chosen because it is also a chemical element like Selenium,
but it is lighter.

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