bjesus/pipet

Swiss-army tool for scraping and extracting data from online assets, made for hackers

Pipet

a swiss-army tool for scraping and extracting data from online assets, made for hackers

Pipet is a command line based web scraper. It supports 3 modes of operation - HTML parsing, JSON parsing, and client-side JavaScript evaluation. It relies heavily on existing tools like curl, and it uses unix pipes for extending its built-in capabilities.

You can use Pipet to track a shipment, get notified when concert tickets are available, stock price changes, and any other kind of information that appears online.

Try it out!

1. Create a hackernews.pipet file containing this:

curl https://news.ycombinator.com/
.title .titleline
  span > a
  .sitebit a

2. Run go run github.com/bjesus/pipet/cmd/pipet@latest hackernews.pipet or install Pipet and run pipet hackernews.pipet
3. See all of the latest hacker news in your terminal!

Use custom separators

Use the --separator (or -s) flag to specify custom separators for text output. For example, run pipet -s "\n" -s "->" hackernews.pipet to see each item in a new line, with -> between the title and the domain.

Get as JSON

Use the --json flag to make Pipet collect the results into a nice JSON. For example, run pipet --json hackernews.pipet to get a JSON representation of the above results.

Render to a template

Add a template file called hackernews.tpl next to your hackernews.pipet file with this content:

<ul>
  {{range $index, $item := index (index . 0) 0}}
    <li>{{index $item 0}} ({{index $item 1}})</li>
  {{end}}
</ul>

Now run pipet hackernews.pipet again and Pipet will automatically detect your template file, and render the results to it.

Use pipes

Use Unix pipes after your queries, as if they were running in your shell. For example, count the characters in each title (with wc) and extract the full article URL (with htmlq):

curl https://news.ycombinator.com/
.title .titleline
  span > a
  span > a | wc -c
  .sitebit a
  .sitebit a | htmlq --attribute href a

Monitor for changes

Set an interval and a command to run on change, and have Pipet notify you when something happened. For example, get a notification whenever the Hacker News #1 story is different:

curl https://news.ycombinator.com/
.title .titleline a

Run it with pipet --interval 60 --on-change "notify-send {}" hackernews.pipet

Installation

Pre-built

Download the latest release from the Releases page. chmod +x pipet and run ./pipet.

Compile

This installation method requires Go to be installed on your system. You can use Go to install Pipet using go install github.com/bjesus/pipet/cmd/pipet@latest. Otherwise you can run it without installing using go run.

Distros

Packages are currently available for Arch Linux, Homebrew and Nix.

Usage

The only required argument for Pipet is the path to your .pipet file. Other than this, the pipet command accepts the following flags:

• --json, -j - Output as JSON (default: false)
• --template value, -t value - Specify a path to a template file. You can also simply name the file like your .pipet file but with a .tpl extension for it to be auto-detected.
• --separator value, -s value - Set a separator for text output (can be used multiple times for setting different separators for different levels of data nesting)
• ---max-pages value, -p value - Maximum number of pages to scrape (default: 3)
• --interval value, -i value - Rerun Pipet after X seconds. Use 0 to disable (default: 0)
• --on-change value, -c value - A command to run when the pipet result is new
• --verbose, -v - Enable verbose logging (default: false)
• --version - Print the Pipet version
• --help, -h - Show help

Pipet files

Pipet files describe where and how to get the data you are interested in. They are normal text files containing one or more blocks separated by an empty line. Lines beginning with // are ignored and can be used for comments. Every block can have 3 sections:

1. Resource - The first line containing the URL and the tool we are using for scraping
2. Queries - The following lines describing the selectors reaching the data we would like scrap
3. Next page - An optional last line starting with > describing the selector pointing to the "next page" of data

Below is an example Pipet file.

// Read Wikipedia's "On This Day" and the subject of today's featured article
curl https://en.wikipedia.org/wiki/Main_Page
div#mp-otd li
  body
div#mp-tfa > p > b > a

// Get the weather in Alert, Canada
curl https://wttr.in/Alert%20Canada?format=j1
current_condition.0.FeelsLikeC
current_condition.0.FeelsLikeF

// Check how popular the Pipet repo is
playwright https://github.com/bjesus/pipet
Array.from(document.querySelectorAll('.about-margin .Link')).map(e => e.innerText.trim()).filter(t=> /^\d/.test(t) )

Resource

Resource lines can start with either curl or playwright.

curl

Resource lines starting with curl will be executed using curl. This is meant so that you can use your browser to find the request containing the information you are interested in, right click it, choose "Copy as cURL", and paste in your Pipet file. This ensures that your headers and cookies are all the same, making it very easy to get data that is behind a login page or hidden from bots. For example, this is a perfectly valid first line for a block: curl 'https://news.ycombinator.com/' --compressed -H 'User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:131.0) Gecko/20100101 Firefox/131.0' -H 'Accept: text/html,application/xhtml+xml,application/xml;q=0.9,image/avif,image/webp,image/png,image/svg+xml,*/*;q=0.8' -H 'Accept-Language: en-US,en;q=0.5' -H 'Accept-Encoding: gzip, deflate, br, zstd' -H 'DNT: 1' -H 'Sec-GPC: 1' -H 'Connection: keep-alive' -H 'Upgrade-Insecure-Requests: 1' -H 'Sec-Fetch-Dest: document' -H 'Sec-Fetch-Mode: navigate' -H 'Sec-Fetch-Site: none' -H 'Sec-Fetch-User: ?1' -H 'Priority: u=0, i' -H 'Pragma: no-cache' -H 'Cache-Control: no-cache' -H 'TE: trailers'.

Playwright

Resource lines starting with playwright will use a headless browser to navigate to the specified URL. If you don't have a headless browser installed, Pipet will attempt to download one for you.

Queries

Query lines define 3 things:

1. The way to the exact pieces of data you would like to extract (e.g. using CSS selectors)
2. The data structure your output will use (e.g. every title and URL should be grouped together by item)
3. The way the data will be processed (e.g. using Unix pipes) before it is printed

Pipet uses 3 different query types - for HTML, for JSON, and for when loading pages with Playwright.

HTML Queries

HTML Queries use CSS Selectors to select specific elements. Whitespace nesting is used for iterations - parent lines will run as iterators, making their children lines run for each occurrence of the parent selector. This means that you can use nesting to determine the structure of your final output. See the following 3 examples:

Get only the first title and first URL

curl https://news.ycombinator.com/
.title .titleline > a
.sitebit a

Get all the titles, and then get all URLs

curl https://news.ycombinator.com/
.title .titleline
  span > a
.title .titleline
  .sitebit a

Get all the title and URL for each story

curl https://news.ycombinator.com/
.title .titleline
  span > a
  .sitebit a

When writing your child selectors, note that the whole document isn't available anymore. Pipet is passing only your parent HTML to the child iterations.

By default, Pipet will return the innerText of your elements. If you need to another piece of data, use Unix pipes. When piping HTML elements, Pipet will pipe the element's complete HTML. For example, you can use | htmq --attr href a to extract the href attribute from links.

JSON Queries

JSON Queries use the GJSON syntax to select specific elements. Here too, whitespace nesting is used for iterations - parent lines will run as iterators, making their children lines run for each occurrence of the parent selector. If you don't like GJSON, that's okay. For example, you can use jq by passing parts or the complete JSON to it using Unix pipes, like @this | jq '.[].firstName'.

When using pipes, Pipet will attempt to parse the returned string. If it's valid JSON, it will be parsed and injected as an object into the Pipet result.

Querying and jq usage

The example below will return the latest water temperature in Amsterdam NDSM, and then pipe the complete JSON to jq so it will combine the coordinates of the reading into one field.

curl https://waterinfo.rws.nl/api/detail/get?locationSlug=NDSM-werf-(o)(NDS1)&mapType=watertemperatuur
latest.data
@this | jq -r '"\(.coordinatex), \(.coordinatey)"'

Iterations

This will return times for bus deparatures. Note the two types of iterations - the first line is GJSON query that returns the ExpectedDepartureTime for each trip, while the the following lines iterates over each trip object using the nested lines below it, allowing us to return multiple keys - ExpectedDepartureTime & TripStopStatus.

curl http://v0.ovapi.nl/tpc/30005093
30005093.Passes.@values.#.ExpectedDepartureTime
30005093.Passes.@values
  ExpectedDepartureTime
  TripStopStatus

CSV export

We can create a simple CSV file by using the previous iteration and configurating a separator

curl http://v0.ovapi.nl/tpc/30005093
30005093.Passes.@values
  ExpectedDepartureTime
  TripStopStatus

Run using pipet -s '\n' water.pipet > output.csv to generate a CSV file.

Playwright Queries

Playwright Queries are different and do not use whitespace nesting. Instead, queries here are simply JavaScript code that will be evaluated after the webpage loaded. If the JavaScript code returns something that can be serialized as JSON, it will be included in Pipet's output. Otherwise, you can write JavaScript that will click, scroll or perform any other action you might want.

Simple Playwright example

This example will return a string like 80 stars, 2 watching, 2 forks after visiting the Pipet repo on Github.

playwright https://github.com/bjesus/pipet
Array.from(document.querySelectorAll('.about-margin .Link')).map(e => e.innerText.trim()).filter(t=> /^\d/.test(t) )

Note that if you copy the second line and paste it in your browser console while visiting https://github.com/bjesus/pipet, you'd get exactly the same result. The vice-versa is also true - if your code worked in the browser, it should work in Pipet too.

Next page

The Next Page line lets you specify a CSS selector that will be used to determine the link to the next page of data. Pipet will then follow it and execute the same queries over it. For example, see this hackernews.pipet file:

curl https://news.ycombinator.com/
.title .titleline
  span > a
  .sitebit a
> a.morelink

The Next Page line is currently only available when working with curl and HTML files.