Meeseeks v0.15.1 Meeseeks View Source

Meeseeks is an Elixir library for parsing and extracting data from HTML and XML with CSS or XPath selectors.

import Meeseeks.CSS

html = HTTPoison.get!("https://news.ycombinator.com/").body

for story <- Meeseeks.all(html, css("tr.athing")) do
  title = Meeseeks.one(story, css(".title a"))

  %{title: Meeseeks.text(title),
    url: Meeseeks.attr(title, "href")}
end
#=> [%{title: "...", url: "..."}, %{title: "...", url: "..."}, ...]

Getting Started

Parse

Start by parsing a source (HTML/XML string or Meeseeks.TupleTree) into a Meeseeks.Document so that it can be queried.

Meeseeks.parse/1 parses the source as HTML, but Meeseeks.parse/2 accepts a second argument of either :html or :xml that specifies how the source is parsed.

document = Meeseeks.parse("<div id=main><p>1</p><p>2</p><p>3</p></div>")
#=> Meeseeks.Document<{...}>

The selection functions accept an unparsed source, parsing it as HTML, but parsing is expensive so parse ahead of time when running multiple selections on the same document.

Select

Next, use one of Meeseeks's selection functions - fetch_all, all, fetch_one, or one - to search for nodes.

All these functions accept a queryable (a source, a document, or a Meeseeks.Result), one or more Meeseeks.Selectors, and optionally an initial context.

all returns a (possibly empty) list of results representing every node matching one of the provided selectors, while one returns a result representing the first node to match a selector (depth-first) or nil if there is no match.

fetch_all and fetch_one work like all and one respectively, but wrap the result in {:ok, ...} if there is a match or return {:error, %Meeseeks.Error{type: :select, reason: :no_match}} if there is not.

To generate selectors, use the css macro provided by Meeseeks.CSS or the xpath macro provided by Meeseeks.XPath.

import Meeseeks.CSS
result = Meeseeks.one(document, css("#main p"))
#=> #Meeseeks.Result<{ <p>1</p> }>

import Meeseeks.XPath
result = Meeseeks.one(document, xpath("//*[@id='main']//p"))
#=> #Meeseeks.Result<{ <p>1</p> }>

Extract

Retrieve information from the Meeseeks.Result with an extraction function.

The extraction functions are attr, attrs, data, dataset, html, own_text, tag, text, tree.

Meeseeks.tag(result)
#=> "p"
Meeseeks.text(result)
#=> "1"
Meeseeks.tree(result)
#=> {"p", [], ["1"]}

The extraction functions html and tree work on Meeseeks.Documents in addition to Meeseeks.Results.

Meeseeks.html(document)
#=> "<html><head></head><body><div id=\"main\"><p>1</p><p>2</p><p>3</p></div></body></html>"

Link to this section Summary

Functions

Returns [Result, ...] if one or more nodes in the queryable match a selector, or [] if none do.

Returns the value of an attribute in a result, or nil if there isn't one.

Returns a result's attributes list, which may be empty, or nil if the result represents a node without attributes.

Returns the combined data of a result or the result's children, which may be an empty string.

Returns a map of a result's data attributes, or nil if the result represents a node without attributes.

Returns {:ok, [Result, ...]} if one of more nodes in the queryable match a selector, or {:error, %Meeseeks.Error{type: :select, reason: :no_match}} if none do.

Returns {:ok, Result} for the first node in the queryable (depth-first) matching a selector, or {:error, %Meeseeks.Error{type: :select, reason: :no_match}} if none do.

Returns a string representing the combined HTML of a document or result and its descendants.

Returns a Result for the first node in the queryable (depth-first) matching a selector, or nil if none do.

Returns the combined text of a result or the result's children, which may be an empty string.

Returns the accumulated result of walking the queryable, accumulating nodes that match a selector. Prefer all or one- select should only be used when a custom accumulator is required.

Returns a result's tag, or nil if the result represents a node without a tag.

Returns the combined text of a result or the result's descendants, which may be an empty string.

Returns the Meeseeks.TupleTree of a document or result and its descendants.

Link to this section Types

Link to this type

queryable()

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queryable() ::
  Meeseeks.Parser.source() | Meeseeks.Document.t() | Meeseeks.Result.t()

Link to this section Functions

Link to this function

all(queryable, selectors)

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all(queryable(), selectors()) ::
  [Meeseeks.Result.t()] | {:error, Meeseeks.Error.t()}

Returns [Result, ...] if one or more nodes in the queryable match a selector, or [] if none do.

Optionally accepts a Meeseeks.Context map.

Parses the source if it is not a Meeseeks.Document or Meeseeks.Result, and may return {:error, %Meeseeks.Error{type: parser} if there is a parse error.

If multiple selections are being ran on the same unparsed source, parse first to avoid unnecessary computation.

Examples

iex> import Meeseeks.CSS
iex> Meeseeks.all("<div id=main><p>1</p><p>2</p><p>3</p></div>", css("#main p")) |> List.first()
#Meeseeks.Result<{ <p>1</p> }>
Link to this function

all(queryable, selectors, context)

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Link to this function

attr(extractable, attribute)

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attr(extractable(), String.t()) :: String.t() | nil

Returns the value of an attribute in a result, or nil if there isn't one.

Nil input returns nil.

Examples

iex> import Meeseeks.CSS
iex> result = Meeseeks.one("<div id=example>Hi</div>", css("#example"))
#Meeseeks.Result<{ <div id="example">Hi</div> }>
iex> Meeseeks.attr(result, "id")
"example"
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attrs(extractable)

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attrs(extractable()) :: [{String.t(), String.t()}] | nil

Returns a result's attributes list, which may be empty, or nil if the result represents a node without attributes.

Nil input returns nil.

Examples

iex> import Meeseeks.CSS
iex> result = Meeseeks.one("<div id=example>Hi</div>", css("#example"))
#Meeseeks.Result<{ <div id="example">Hi</div> }>
iex> Meeseeks.attrs(result)
[{"id", "example"}]
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data(extractable, opts \\ [])

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data(extractable(), Keyword.t()) :: String.t() | nil

Returns the combined data of a result or the result's children, which may be an empty string.

Once the data has been combined the whitespace is compacted by replacing all instances of more than one whitespace character with a single space and then trimmed.

Data is the content of <script> or <style> tags, or the content of comments starting with "[CDATA[" and ending with "]]". The latter behavior is to support the extraction of CDATA from HTML, since HTML5 parsers parse CDATA as comments.

Nil input returns nil.

Options

  • :collapse_whitespace - Boolean determining whether or not to replace blocks of whitespace with a single space character. Defaults to true.
  • :trim - Boolean determining whether or not to trim the resulting text. Defaults to true.

Examples

iex> import Meeseeks.CSS
iex> result1 = Meeseeks.one("<div id=example>Hi</div>", css("#example"))
#Meeseeks.Result<{ <div id="example">Hi</div> }>
iex> Meeseeks.data(result1)
""
iex> result2 = Meeseeks.one("<script id=example>Hi</script>", css("#example"))
#Meeseeks.Result<{ <script id="example">Hi</script> }>
iex> Meeseeks.data(result2)
"Hi"
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dataset(extractable)

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dataset(extractable()) :: %{optional(String.t()) => String.t()} | nil

Returns a map of a result's data attributes, or nil if the result represents a node without attributes.

Behaves like HTMLElement.dataset; only valid data attributes are included, and attribute names have "data-" removed and are converted to camelCase.

See: https://developer.mozilla.org/en-US/docs/Web/API/HTMLElement/dataset

Nil input returns nil.

Examples

iex> import Meeseeks.CSS
iex> result = Meeseeks.one("<div id=example data-x-val=1 data-y-val=2></div>", css("#example"))
#Meeseeks.Result<{ <div id="example" data-x-val="1" data-y-val="2"></div> }>
iex> Meeseeks.dataset(result)
%{"xVal" => "1", "yVal" => "2"}
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fetch_all(queryable, selectors)

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fetch_all(queryable(), selectors()) ::
  {:ok, [Meeseeks.Result.t()]} | {:error, Meeseeks.Error.t()}

Returns {:ok, [Result, ...]} if one of more nodes in the queryable match a selector, or {:error, %Meeseeks.Error{type: :select, reason: :no_match}} if none do.

Optionally accepts a Meeseeks.Context map.

Parses the source if it is not a Meeseeks.Document or Meeseeks.Result, and may return {:error, %Meeseeks.Error{type: parser} if there is a parse error.

If multiple selections are being ran on the same unparsed source, parse first to avoid unnecessary computation.

Examples

iex> import Meeseeks.CSS
iex> Meeseeks.fetch_all("<div id=main><p>1</p><p>2</p><p>3</p></div>", css("#main p")) |> elem(1) |> List.first()
#Meeseeks.Result<{ <p>1</p> }>
Link to this function

fetch_all(queryable, selectors, context)

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fetch_all(queryable(), selectors(), Meeseeks.Context.t()) ::
  {:ok, [Meeseeks.Result.t()]} | {:error, Meeseeks.Error.t()}
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fetch_one(queryable, selectors)

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fetch_one(queryable(), selectors()) ::
  {:ok, Meeseeks.Result.t()} | {:error, Meeseeks.Error.t()}

Returns {:ok, Result} for the first node in the queryable (depth-first) matching a selector, or {:error, %Meeseeks.Error{type: :select, reason: :no_match}} if none do.

Optionally accepts a Meeseeks.Context map.

Parses the source if it is not a Meeseeks.Document or Meeseeks.Result, and may return {:error, %Meeseeks.Error{type: parser} if there is a parse error.

If multiple selections are being ran on the same unparsed source, parse first to avoid unnecessary computation.

Examples

iex> import Meeseeks.CSS
iex> Meeseeks.fetch_one("<div id=main><p>1</p><p>2</p><p>3</p></div>", css("#main p")) |> elem(1)
#Meeseeks.Result<{ <p>1</p> }>
Link to this function

fetch_one(queryable, selectors, context)

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fetch_one(queryable(), selectors(), Meeseeks.Context.t()) ::
  {:ok, Meeseeks.Result.t()} | {:error, Meeseeks.Error.t()}
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html(extractable)

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html(extractable()) :: String.t() | nil

Returns a string representing the combined HTML of a document or result and its descendants.

Nil input returns nil.

Examples

iex> import Meeseeks.CSS
iex> document = Meeseeks.parse("<div id=example>Hi</div>")
iex> Meeseeks.html(document)
"<html><head></head><body><div id=\"example\">Hi</div></body></html>"
iex> result = Meeseeks.one(document, css("#example"))
#Meeseeks.Result<{ <div id="example">Hi</div> }>
iex> Meeseeks.html(result)
"<div id=\"example\">Hi</div>"
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one(queryable, selectors)

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one(queryable(), selectors()) ::
  Meeseeks.Result.t() | nil | {:error, Meeseeks.Error.t()}

Returns a Result for the first node in the queryable (depth-first) matching a selector, or nil if none do.

Optionally accepts a Meeseeks.Context map.

Parses the source if it is not a Meeseeks.Document or Meeseeks.Result, and may return {:error, %Meeseeks.Error{type: parser} if there is a parse error.

If multiple selections are being ran on the same unparsed source, parse first to avoid unnecessary computation.

Examples

iex> import Meeseeks.CSS
iex> Meeseeks.one("<div id=main><p>1</p><p>2</p><p>3</p></div>", css("#main p"))
#Meeseeks.Result<{ <p>1</p> }>
Link to this function

one(queryable, selectors, context)

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Link to this function

own_text(extractable, opts \\ [])

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own_text(extractable(), Keyword.t()) :: String.t() | nil

Returns the combined text of a result or the result's children, which may be an empty string.

Once the text has been combined the whitespace is compacted by replacing all instances of more than one whitespace character with a single space and then trimmed.

Nil input returns nil.

Options

  • :collapse_whitespace - Boolean determining whether or not to replace blocks of whitespace with a single space character. Defaults to true.
  • :trim - Boolean determining whether or not to trim the resulting text. Defaults to true.

Examples

iex> import Meeseeks.CSS
iex> result = Meeseeks.one("<div>Hello, <b>World!</b></div>", css("div"))
#Meeseeks.Result<{ <div>Hello, <b>World!</b></div> }>
iex> Meeseeks.own_text(result)
"Hello,"
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parse(source)

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parse(Meeseeks.Parser.source()) ::
  Meeseeks.Document.t() | {:error, Meeseeks.Error.t()}

Parses a string or Meeseeks.TupleTree into a Meeseeks.Document.

parse/1 parses as HTML, while parse/2 accepts a second argument of either :html, :xml, or tuple_tree that specifies how the source is parsed.

Examples

iex> Meeseeks.parse("<div id=main><p>Hello, Meeseeks!</p></div>")
#Meeseeks.Document<{...}>

iex> Meeseeks.parse("<book><author>GGK</author></book>", :xml)
#Meeseeks.Document<{...}>

iex> Meeseeks.parse({"div", [{"id", "main"}], [{"p", [], ["Hello, Meeseeks!"]}]}, :tuple_tree)
#Meeseeks.Document<{...}>
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parse(source, parser)

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parse(Meeseeks.Parser.source(), Meeseeks.Parser.type()) ::
  Meeseeks.Document.t() | {:error, Meeseeks.Error.t()}
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select(queryable, selectors, context)

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select(queryable(), selectors(), Meeseeks.Context.t()) ::
  any() | {:error, Meeseeks.Error.t()}

Returns the accumulated result of walking the queryable, accumulating nodes that match a selector. Prefer all or one- select should only be used when a custom accumulator is required.

Requires that a Meeseeks.Accumulator has been added to the context via Meeseeks.Context.add_accumulator/2, and will raise an error if it hasn't.

Parses the source if it is not a Meeseeks.Document or Meeseeks.Result, and may return {:error, %Meeseeks.Error{type: parser} if there is a parse error.

If multiple selections are being ran on the same unparsed source, parse first to avoid unnecessary computation.

Examples

iex> import Meeseeks.CSS
iex> accumulator = %Meeseeks.Accumulator.One{}
iex> context = Meeseeks.Context.add_accumulator(%{}, accumulator)
iex> Meeseeks.select("<div id=main><p>1</p><p>2</p><p>3</p></div>", css("#main p"), context)
#Meeseeks.Result<{ <p>1</p> }>

Returns a result's tag, or nil if the result represents a node without a tag.

Nil input returns nil.

Examples

iex> import Meeseeks.CSS
iex> result = Meeseeks.one("<div id=example>Hi</div>", css("#example"))
#Meeseeks.Result<{ <div id="example">Hi</div> }>
iex> Meeseeks.tag(result)
"div"
Link to this function

text(extractable, opts \\ [])

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text(extractable(), Keyword.t()) :: String.t() | nil

Returns the combined text of a result or the result's descendants, which may be an empty string.

Once the text has been combined the whitespace is compacted by replacing all instances of more than one whitespace character with a single space and then trimmed.

Nil input returns nil.

Options

  • :collapse_whitespace - Boolean determining whether or not to replace blocks of whitespace with a single space character. Defaults to true.
  • :trim - Boolean determining whether or not to trim the resulting text. Defaults to true.

Examples

iex> import Meeseeks.CSS
iex> result = Meeseeks.one("<div>Hello, <b>World!</b></div>", css("div"))
#Meeseeks.Result<{ <div>Hello, <b>World!</b></div> }>
iex> Meeseeks.text(result)
"Hello, World!"

Returns the Meeseeks.TupleTree of a document or result and its descendants.

Nil input returns nil.

Examples

iex> import Meeseeks.CSS
iex> document = Meeseeks.parse("<div id=example>Hi</div>")
iex> Meeseeks.tree(document)
[{"html", [],
  [{"head", [], []},
   {"body", [], [{"div", [{"id", "example"}], ["Hi"]}]}]}]
iex> result = Meeseeks.one(document, css("#example"))
#Meeseeks.Result<{ <div id="example">Hi</div> }>
iex> Meeseeks.tree(result)
{"div", [{"id", "example"}], ["Hi"]}