urlwatch: A Python repository from ishanarora

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                                  ... monitors webpages for you

urlwatch is intended to help you watch changes in webpages and get notified (via e-mail, in your terminal or through various third party services) of any changes. The change notification will include the URL that has changed and a unified diff of what has changed.

DEPENDENCIES

urlwatch 2 requires:

Python 3.5 or newer
PyYAML
minidb
requests
keyring
appdirs
lxml
cssselect
enum34 (Python 3.3 only)

The dependencies can be installed with (add --user to install to $HOME):

python3 -m pip install pyyaml minidb requests keyring appdirs lxml cssselect

Optional dependencies (install via python3 -m pip install <packagename>):

Pushover reporter: chump
Pushbullet reporter: pushbullet.py
Stdout reporter with color on Windows: colorama
"browser" job kind: requests-html
Unit testing: pycodestyle

QUICK START

Start urlwatch to migrate your old data or start fresh
Use urlwatch --edit to customize your job list (this will create/edit urls.yaml)
Use urlwatch --edit-config if you want to set up e-mail sending
Use urlwatch --edit-hooks if you want to write custom subclasses
Add urlwatch to your crontab (crontab -e) to monitor webpages periodically

The checking interval is defined by how often you run urlwatch. You can use e.g. crontab.guru to figure out the schedule expression for the checking interval, we recommend not more often than 30 minutes (this would be */30 * * * *). If you have never used cron before, check out the crontab command help.

On Windows, cron is not installed by default. Use the Windows Task Scheduler instead, or see this StackOverflow question for alternatives.

TIPS AND TRICKS

Quickly adding new URLs to the job list from the command line:

urlwatch --add url=http://example.org,name=Example

You can pick only a given HTML element with the built-in filter, for example to extract <div id="something">.../<div> from a page, you can use the following in your urls.yaml:

url: http://example.org/
filter: element-by-id:something

Also, you can chain filters, so you can run html2text on the result:

url: http://example.net/
filter: element-by-id:something,html2text

The example urls.yaml file also demonstrates the use of built-in filters, here 3 filters are used: html2text, line-grep and whitespace removal to get just a certain info field from a webpage:

url: https://thp.io/2008/urlwatch/
filter: html2text,grep:Current.*version,strip

For most cases, this means that you can specify a filter chain in your urls.yaml page without requiring a custom hook where previously you would have needed to write custom filtering code in Python.

If you are using the grep filter, you can grep for a comma (,) by using \054 (: does not need to be escaped separately and can be used as-is), for example to convert HTML to text, then grep for a,b:, and then strip whitespace, use this:

url: https://example.org/
filter: html2text,grep:a\054b:,strip

If you want to extract only the body tag you can use this filer:

url: https://thp.io/2008/urlwatch/
filter: element-by-tag:body

You can also specify an external diff-style tool (a tool that takes two filenames (old, new) as parameter and returns on its standard output the difference of the files), for example to use GNU wdiff to get word-based differences instead of line-based difference:

url: https://example.com/
diff_tool: wdiff

Note that diff_tool specifies an external command-line tool, so that tool must be installed separately (e.g. apt install wdiff on Debian or brew install wdiff on macOS). Coloring is supported for wdiff-style output, but potentially not for other diff tools.

To filter based on an XPath expression, you can use the xpath filter like so (see Microsoft's XPath Examples page for some other examples):

url: https://example.net/
filter: xpath:/body

This filters only the <body> element of the HTML document, stripping out everything else.

To filter based on a CSS selector, you can use the css filter like so:

url: https://example.net/
filter: css:body

Some limitations and extensions exist as explained in cssselect's documentation.

In some cases, it might be useful to ignore (temporary) network errors to avoid notifications being sent. While there is a display.error config option (defaulting to True) to control reporting of errors globally, to ignore network errors for specific jobs only, you can use the ignore_connection_errors key in the job list configuration file:

url: https://example.com/
ignore_connection_errors: true

Similarly, you might want to ignore some (temporary) HTTP errors on the server side:

url: https://example.com/
ignore_http_error_codes: 408, 429, 500, 502, 503, 504

or ignore all HTTP errors if you like:

url: https://example.com/
ignore_http_error_codes: 4xx, 5xx

For web pages with misconfigured HTTP headers or rare encodings, it may be useful to explicitly specify an encoding from Python's Standard Encodings.

url: https://example.com/
encoding: utf-8

By default, url jobs timeout after 60 seconds. If you want a different timeout period, use the timeout key to specify it in number of seconds, or set it to 0 to never timeout.

url: https://example.com/
timeout: 300

If you want to change some settings for all your jobs, edit the job_defaults section in your config file:

...
job_defaults:
  all:
    diff_tool: wdiff
  url:
    ignore_connection_errors: true

The above config file sets all jobs to use wdiff as diff tool, and all "url" jobs to ignore connection errors.

PUSHOVER

You can configure urlwatch to send real time notifications about changes via Pushover(https://pushover.net/). To enable this, ensure you have the chump python package installed (see DEPENDENCIES). Then edit your config (urlwatch --edit-config) and enable pushover. You will also need to add to the config your Pushover user key and a unique app key (generated by registering urlwatch as an application on your Pushover account(https://pushover.net/apps/build).

You can send to a specific device by using the device name, as indicated when you add or view your list of devices in the Pushover console. For example device: 'MyPhone', or device: 'MyLaptop'. To send to all of your devices, set device: null in your config (urlwatch --edit-config) or leave out the device configuration completely.

PUSHBULLET

Pushbullet notifications are configured similarly to Pushover (see above). You'll need to add to the config your Pushbullet Access Token, which you can generate at https://www.pushbullet.com/#settings

Telegram notifications are configured using the Telegram Bot API. For this, you'll need a Bot API token and a chat id (see https://core.telegram.org/bots). Sample configuration:

telegram:
  bot_token: '999999999:3tOhy2CuZE0pTaCtszRfKpnagOG8IQbP5gf' # your bot api token
  chat_id: '88888888' # the chat id where the messages should be sent
  enabled: true

To set up Telegram, from your Telegram app, chat up BotFather (New Message, Search, "BotFather"), then say /newbot and follow the instructions. Eventually it will tell you the bot token (in the form seen above, <number>:<random string>) - add this to your config file.

You can then click on the link of your bot, which will send the message /start. At this point, you can use the command urlwatch --telegram-chats to list the private chats the bot is involved with. This is the chat ID that you need to put into the config file as chat_id. You may add multiple chat IDs as a YAML list:

telegram:
  bot_token: '999999999:3tOhy2CuZE0pTaCtszRfKpnagOG8IQbP5gf' # your bot api token
  chat_id:
    - '11111111'
    - '22222222'
  enabled: true

Don't forget to also enable the reporter.

SLACK

Slack notifications are configured using "Slack Incoming Webhooks". Here is a sample configuration:

slack:
  webhook_url: 'https://hooks.slack.com/services/T50TXXXXXU/BDVYYYYYYY/PWTqwyFM7CcCfGnNzdyDYZ'
  enabled: true

To set up Slack, from you Slack Team, create a new app and activate "Incoming Webhooks" on a channel, you'll get a webhook URL, copy it into the configuration as seen above.

You can use the command urlwatch --test-slack to test if the Slack integration works.

BROWSER

If the webpage you are trying to watch runs client-side JavaScript to render the page, Requests-HTML can now be used to render the page in a headless Chromium instance first and then use the HTML of the resulting page.

Use the browser kind in the configuration and the navigate key to set the URL to retrieve. note that the normal url job keys are not supported for the browser job types at the moment, for example:

kind: browser
name: "A Page With JavaScript"
navigate: http://example.org/

E-MAIL VIA GMAIL SMTP

You need to configure your GMail account to allow for "less secure" (password-based) apps to login:

Go to https://myaccount.google.com/
Click on "Sign-in & security"
Scroll all the way down to "Allow less secure apps" and enable it

Now, start the configuration editor: urlwatch --edit-config

These are the keys you need to configure (see #158):

report/email/enabled: true
report/email/from: your.username@gmail.com (edit accordingly)
report/email/method: smtp
report/email/smtp/host: smtp.gmail.com
report/email/smtp/auth: true
report/email/smtp/port: 587
report/email/smtp/starttls: true
report/email/to: The e-mail address you want to send reports to

Now, for setting the password, it's not stored in the config file, but in your keychain. To store the password, run: urlwatch --smtp-login and enter your password.

E-MAIL VIA AMAZON SIMPLE EMAIL SERVICE (SES)

Start the configuration editor: urlwatch --edit-config

These are the keys you need to configure:

report/email/enabled: true
report/email/from: you@verified_domain.com (edit accordingly)
report/email/method: smtp
report/email/smtp/host: email-smtp.us-west-2.amazonaws.com (edit accordingly)
report/email/smtp/user: ABCDEFGHIJ1234567890 (edit accordingly)
report/email/smtp/auth: true
report/email/smtp/port: 587 (25 or 465 also work)
report/email/smtp/starttls: true
report/email/to: The e-mail address you want to send reports to

The password is not stored in the config file, but in your keychain. To store the password, run: urlwatch --smtp-login and enter your password.

SMTP LOGIN WITHOUT KEYRING

If for whatever reason you cannot use a keyring to store your password (for example, when using it from a cron job) you can also set the insecure_password option in the SMTP config:

report/email/smtp/auth: true
report/email/smtp/insecure_password: secret123

The insecure_password key will be preferred over the data stored in the keyring. Please note that as the name says, storing the password as plaintext in the configuration is insecure and bad practice, but for an e-mail account that's only dedicated for sending mails this might be a way. Never ever use this with your your primary e-mail account! Seriously! Create a throw-away GMail (or other) account just for sending out those e-mails or use local sendmail with a mail server configured instead of relying on SMTP and password auth.

Note that this makes it really easy for your password to be picked up by software running on your machine, by other users logged into the system and/or for the password to appear in log files accidentally.

TESTING FILTERS

While creating your filter pipeline, you might want to preview what the filtered output looks like. You can do so by first configuring your job and then running urlwatch with the --test-filter command, passing in the index (from --list) or the URL/location of the job to be tested:

urlwatch --test-filter 1   # Test the first job in the list
urlwatch --test-filter https://example.net/  # Test the job with the given URL

The output of this command will be the filtered plaintext of the job, this is the output that will (in a real urlwatch run) be the input to the diff algorithm.

SENDING COOKIES

It is possible to add cookies to HTTP requests for pages that need it, the YAML syntax for this is:

url: http://example.com/
cookies:
    Key: ValueForKey
    OtherKey: OtherValue

WATCHING GITHUB RELEASES

This is an example how to watch the GitHub "releases" page for a given project for the latest release version, to be notified of new releases:

url: "https://github.com/thp/urlwatch/releases/latest"
filter:
  - xpath: '(//div[contains(@class,"release-timeline-tags")]//h4)[1]/a'
  - html2text: re

USING XPATH AND CSS FILTERS WITH XML AND EXCLUSIONS

By default, XPath and CSS filters are set up for HTML documents. However, it is possible to use them for XML documents as well (these examples parse an RSS feed and filter only the titles and publication dates):

url: 'https://heronebag.com/blog/index.xml'
filter:
  - xpath:
      path: '//item/title/text()|//item/pubDate/text()'
      method: xml

url: 'https://heronebag.com/blog/index.xml'
filter:
  - css:
      selector: 'item > title, item > pubDate'
      method: xml
  - html2text: re

To match an element in an XML namespace, use a namespace prefix before the tag name. Use a : to seperate the namespace prefix and the tag name in an XPath expression, and use a | in a CSS selector.

url: 'https://www.wired.com/feed/rss'
filter:
  - xpath:
      path: '//item/media:keywords'
      method: xml
      namespaces:
        media: http://search.yahoo.com/mrss/

url: 'https://www.wired.com/feed/rss'
filter:
  - css:
      selector: 'item > media|keywords'
      method: xml
      namespaces:
        media: http://search.yahoo.com/mrss/

Alternatively, use the XPath expression //*[name()='<tag_name>'] to bypass the namespace entirely.

Another useful option with XPath and CSS filters is exclude. Elements selected by this exclude expression are removed from the final result. For example, the following job will not have any <a> tag in its results:

url: https://example.org/
filter:
  - css:
      selector: 'body'
      exclude: 'a'

COMPARE WITH SEVERAL LATEST SNAPSHOTS

If a webpage frequently changes between several known stable states, it may be desirable to have changes reported only if the webpage changes into a new unknown state. You can use compared_versions to do this.

url: https://example.com/
compared_versions: 3

In this example, changes are only reported if the webpage becomes different from the latest three distinct states. The differences are shown relative to the closest match.

REMOVE OR REPLACE TEXT USING REGULAR EXPRESSIONS

Just like Python's re.sub function, there's the possibility to apply a regular expression and either remove of replace the matched text. The following example applies the filter 3 times:

Just specifying a string as the value will replace the matches with the empty string.
Simple patterns can be replaced with another string using "pattern" as the expression and "repl" as the replacement.
You can use groups (()) and back-reference them with \1 (etc..) to put groups into the replacement string.

All features are described in Python's re.sub documentation (the pattern and repl values are passed to this function as-is, with the value of repl defaulting to the empty string).

kind: url
url: https://example.com/
filter:
    - re.sub: '\s*href="[^"]*"'
    - re.sub:
        pattern: '<h1>'
        repl: 'HEADING 1: '
    - re.sub:
        pattern: '</([^>]*)>'
        repl: '<END OF TAG \1>'

MIGRATION FROM URLWATCH 1.x

Migration from urlwatch 1.x should be automatic on first start. Here is a quick rundown of changes in 2.0:

URLs are stored in a YAML file now, with direct support for specifying names for jobs, different job kinds, directly applying filters, selecting the HTTP request method, specifying POST data as dictionary and much more
The cache directory has been replaced with a SQLite 3 database file "cache.db" in minidb format, storing all change history (use --gc-cache to remove old changes if you don't need them anymore) for further analysis
The hooks mechanism has been replaced with support for creating new job kinds by subclassing, new filters (also by subclassing) as well as new reporters (pieces of code that put the results somewhere, for example the default installation contains the "stdout" reporter that writes to the console and the "email" reporter that can send HTML and text e-mails)
A configuration file - urlwatch.yaml - has been added for specifying user preferences instead of having to supply everything via the command line

CONTACT

Website: https://thp.io/2008/urlwatch/

E-Mail: m@thp.io

ishanarora/urlwatch