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84 lines
2.9 KiB
Markdown
84 lines
2.9 KiB
Markdown
#LuaRock "htmlparser"
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Parse HTML text into a tree of elements with selectors
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##License
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MIT; see `./doc/LICENSE`
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##Usage
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Start off with
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```lua
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require("luarocks.loader")
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local htmlparser = require("htmlparser")
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```
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Then, parse some html:
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```lua
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local root = htmlparser.parse(htmlstring)
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```
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The input to parse may be the contents of a complete html document, or any valid html snippet, as long as all tags are correctly opened and closed.
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Now, find specific elements by selecting:
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```lua
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local elements = root:select(selectorstring)
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```
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Or in shorthand:
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```lua
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local elements = root(selectorstring)
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```
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This wil return a Set of elements, all of which are of the same type as the root element, and thus support selecting as well, if ever needed:
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```lua
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for e in pairs(elements) do
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print(e.name)
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local subs = e(subselectorstring)
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for sub in pairs(subs) do
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print("", sub.name)
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end
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end
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```
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##Selectors
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- `"element"`
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- `"#id"`
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- `".class"`
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- `"[attribute]"`
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- `"[attribute=value]"`
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- `"[attribute!=value]"`
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- `"[attribute|=value]"`
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- `"[attribute*=value]"`
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- `"[attribute~=value]"`
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- `"[attribute^=value]"`
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- `"[attribute$=value]"`
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- `":not(selector)"`
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- `"ancestor descendant"`
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- `"parent > child"`
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Selectors can be combined; e.g. `".class:not([attribute]) element.class"`
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###Limitations
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- Attribute values in selectors currently cannot contain any spaces, since space is interpreted as a delimiter between the `ancestor` and `descendant`, `parent` and `>`, or `>` and `child` parts of the selector
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- Likewise, for the `parent > child` relation, the spaces before and after the `>` are mandatory
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##Examples
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See `./doc/samples.lua`
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##Element type
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All tree elements provide, apart from `:select` and `()`, the following accessors:
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###Basic
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- `.name` = the element's tagname
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- `.attributes` = a table with keys and values for the element's attributes; `{}` if none
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- `.id` = the value of the element's id attribute; `nil` if not present
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- `.classes` = an array with the classes listed in element's class attribute; `{}` if none
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- `:getcontent()` = the raw text between the opening and closing tags of the element; `""` if none
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- `.nodes` = an array with the element's child elements, `{}` if none
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- `.parent` = the elements that contains this element; `root.parent` is `nil`
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###Other
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- `:gettext()` = the raw text of the complete element, starting with `"<tagname"` and ending with `"/>"`
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- `.level` = how deep the element is in the tree; root level is `0`
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- `.root` the root element of the tree; `root.root` is `root`
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- `.deepernodes` = a Set containing all elements in the tree beneath this element, including this element's `.nodes`; `{}` if none
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- `.deeperelements` = a table with a key for each distinct tagname in `.deepernodes`, containing a Set of all deeper element nodes with that name; `{}` in none
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- `.deeperattributes` = as `.deeperelements`, but keyed on attribute name
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- `.deeperids` = as `.deeperelements`, but keyed on id value
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- `.deeperclasses` = as `.deeperelements`, but keyed on class name
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