Pagser

Pagser inspired by page parser。

Pagser is a simple, extensible, configurable parse and deserialize html page to struct based on goquery and struct tags for golang crawler.

Install
Features
Docs
Usage
Configuration
Struct Tag Grammar
Functions
Examples
Dependencies

Install

go get -u github.com/foolin/pagser

Or get the specified version:

go get github.com/foolin/pagser@{version}

The {version} release list: https://github.com/foolin/pagser/releases

Features

Simple - Use golang struct tag syntax.
Easy - Easy use for your spider/crawler/colly application.
Extensible - Support for extension functions.
Struct tag grammar - Grammar is simple, like `pagser:"a->attr(href)"`.
Nested Structure - Support Nested Structure for node.
Configurable - Support configuration.
Implicit type conversion - Automatic implicit type conversion, Output result string convert to int, int64, float64...
GoQuery/Colly - Support all goquery project, such as go-colly.

Docs

See Pagser

Usage

package main

import (
	"encoding/json"
	"github.com/foolin/pagser"
	"log"
)

const rawPageHtml = `
<!doctype html>
<html>
<head>
    <meta charset="utf-8">
    <title>Pagser Title</title>
	<meta name="keywords" content="golang,pagser,goquery,html,page,parser,colly">
</head>

<body>
	<h1>H1 Pagser Example</h1>
	<div class="navlink">
		<div class="container">
			<ul class="clearfix">
				<li id=''><a href="/">Index</a></li>
				<li id='2'><a href="/list/web" title="web site">Web page</a></li>
				<li id='3'><a href="/list/pc" title="pc page">Pc Page</a></li>
				<li id='4'><a href="/list/mobile" title="mobile page">Mobile Page</a></li>
			</ul>
		</div>
	</div>
</body>
</html>
`

type PageData struct {
	Title    string   `pagser:"title"`
	Keywords []string `pagser:"meta[name='keywords']->attrSplit(content)"`
	H1       string   `pagser:"h1"`
	Navs     []struct {
		ID   int    `pagser:"->attrEmpty(id, -1)"`
		Name string `pagser:"a->text()"`
		Url  string `pagser:"a->attr(href)"`
	} `pagser:".navlink li"`
}

func main() {
	//New default config
	p := pagser.New()

	//data parser model
	var data PageData
	//parse html data
	err := p.Parse(&data, rawPageHtml)
	//check error
	if err != nil {
		log.Fatal(err)
	}

	//print data
	log.Printf("Page data json: \n-------------\n%v\n-------------\n", toJson(data))
}

func toJson(v interface{}) string {
	data, _ := json.MarshalIndent(v, "", "\t")
	return string(data)
}

Run output:


Page data json: 
-------------
{
	"Title": "Pagser Title",
	"Keywords": [
		"golang",
		"pagser",
		"goquery",
		"html",
		"page",
		"parser",
		"colly"
	],
	"H1": "H1 Pagser Example",
	"Navs": [
		{
			"ID": -1,
			"Name": "Index",
			"Url": "/"
		},
		{
			"ID": 2,
			"Name": "Web page",
			"Url": "/list/web"
		},
		{
			"ID": 3,
			"Name": "Pc Page",
			"Url": "/list/pc"
		},
		{
			"ID": 4,
			"Name": "Mobile Page",
			"Url": "/list/mobile"
		}
	]
}
-------------

Configuration

type Config struct {
	TagName    string //struct tag name, default is `pagser`
	FuncSymbol   string //Function symbol, default is `->`
	Debug        bool   //Debug mode, debug will print some log, default is `false`
}

Struct Tag Grammar

[goquery selector]->[function]

Example:

type ExamData struct {
	Herf string `pagser:".navLink li a->attr(href)"`
}

1.Struct tag name: pagser
2.goquery selector: .navLink li a
3.Function symbol: ->
4.Function name: attr
5.Function arguments: href

Functions

Builtin functions

text() get element text, return string, this is default function, if not define function in struct tag.

eachText() get each element text, return []string.

html() get element inner html, return string.

eachHtml() get each element inner html, return []string.

outerHtml() get element outer html, return string.

eachOutHtml() get each element outer html, return []string.

attr(name) get element attribute value, return string.

eachAttr() get each element attribute value, return []string.

attrSplit(name, sep) get attribute value and split by separator to array string.

attr('value') get element attribute value by name is value, return string, eg: will return "xxx".

textSplit(sep) get element text and split by separator to array string, return []string.

eachTextJoin(sep) get each element text and join to string, return string.

eq(index) reduces the set of matched elements to the one at the specified index, return Selection for nested struct.

...

More builtin functions see docs: https://pkg.go.dev/github.com/foolin/pagser?tab=doc#BuiltinFunctions

Extension functions

Markdown() //convert html to markdown format.

UgcHtml() //sanitize html

Extensions function need register, like:

import "github.com/foolin/pagser/extensions/markdown"

p := pagser.New()

//Register Markdown
markdown.Register(p)

Custom function

Function interface

type CallFunc func(node *goquery.Selection, args ...string) (out interface{}, err error)

Define global function

//global function need call pagser.RegisterFunc("MyGlob", MyGlobalFunc) before use it.
// this global method must call pagser.RegisterFunc("MyGlob", MyGlobalFunc).
func MyGlobalFunc(node *goquery.Selection, args ...string) (out interface{}, err error) {
	return "Global-" + node.Text(), nil
}

type PageData struct{
  MyGlobalValue string    `pagser:"->MyGlob()"`
}

func main(){

    p := pagser.New()

    //Register global function `MyGlob`
    p.RegisterFunc("MyGlob", MyGlobalFunc)

    //Todo

    //data parser model
    var data PageData
    //parse html data
    err := p.Parse(&data, rawPageHtml)

    //...
}

Define struct function

type PageData struct{
  MyFuncValue int    `pagser:"->MyFunc()"`
}

// this method will auto call, not need register.
func (d PageData) MyFunc(node *goquery.Selection, args ...string) (out interface{}, err error) {
	return "Struct-" + node.Text(), nil
}


func main(){

    p := pagser.New()

    //Todo

    //data parser model
    var data PageData
    //parse html data
    err := p.Parse(&data, rawPageHtml)

    //...
}

Call Syntax

Note: all function arguments are string, single quotes are optional.

Function call with no arguments

->fn()

Function calls with one argument, and single quotes are optional

->fn(one)

->fn('one')

Function calls with many arguments

->fn(one, two, three, ...)

->fn('one', 'two', 'three', ...)

Function calls with single quotes and escape character

->fn('it\'s ok', 'two,xxx', 'three', ...)

Priority Order

Lookup function priority order:

struct method -> parent method -> ... -> global

More Examples

See advance example: https://github.com/foolin/pagser/tree/master/_examples/advance

Implicit type conversion

Automatic implicit type conversion, Output result string convert to int, int64, float64...

Support type:

bool
float32
float64
int
int32
int64
string
[]bool
[]float32
[]float64
[]int
[]int32
[]int64
[]string

Examples

Crawl page example

package main

import (
	"encoding/json"
	"github.com/foolin/pagser"
	"log"
	"net/http"
)

type PageData struct {
	Title    string `pagser:"title"`
	RepoList []struct {
		Names       []string `pagser:"h1->textSplit('/', true)"`
		Description string   `pagser:"h1 + p"`
		Stars       string   `pagser:"a.muted-link->eqAndText(0)"`
		Repo        string   `pagser:"h1 a->attrConcat('href', 'https://github.com', $value, '?from=pagser')"`
	} `pagser:"article.Box-row"`
}

func main() {
	resp, err := http.Get("https://github.com/trending")
	if err != nil {
		log.Fatal(err)
	}
	defer resp.Body.Close()

	//New default config
	p := pagser.New()

	//data parser model
	var data PageData
	//parse html data
	err = p.ParseReader(&data, resp.Body)
	//check error
	if err != nil {
		log.Fatal(err)
	}

	//print data
	log.Printf("Page data json: \n-------------\n%v\n-------------\n", toJson(data))
}

func toJson(v interface{}) string {
	data, _ := json.MarshalIndent(v, "", "\t")
	return string(data)
}

Run output:


2020/04/25 12:26:04 Page data json: 
-------------
{
	"Title": "Trending  repositories on GitHub today · GitHub",
	"RepoList": [
		{
			"Names": [
				"pcottle",
				"learnGitBranching"
			],
			"Description": "An interactive git visualization to challenge and educate!",
			"Stars": "16,010",
			"Repo": "https://github.com/pcottle/learnGitBranching?from=pagser"
		},
		{
			"Names": [
				"jackfrued",
				"Python-100-Days"
			],
			"Description": "Python - 100天从新手到大师",
			"Stars": "83,484",
			"Repo": "https://github.com/jackfrued/Python-100-Days?from=pagser"
		},
		{
			"Names": [
				"brave",
				"brave-browser"
			],
			"Description": "Next generation Brave browser for macOS, Windows, Linux, Android.",
			"Stars": "5,963",
			"Repo": "https://github.com/brave/brave-browser?from=pagser"
		},
		{
			"Names": [
				"MicrosoftDocs",
				"azure-docs"
			],
			"Description": "Open source documentation of Microsoft Azure",
			"Stars": "3,798",
			"Repo": "https://github.com/MicrosoftDocs/azure-docs?from=pagser"
		},
		{
			"Names": [
				"ahmetb",
				"kubectx"
			],
			"Description": "Faster way to switch between clusters and namespaces in kubectl",
			"Stars": "6,979",
			"Repo": "https://github.com/ahmetb/kubectx?from=pagser"
		},

        //...        

		{
			"Names": [
				"serverless",
				"serverless"
			],
			"Description": "Serverless Framework – Build web, mobile and IoT applications with serverless architectures using AWS Lambda, Azure Functions, Google CloudFunctions \u0026 more! –",
			"Stars": "35,502",
			"Repo": "https://github.com/serverless/serverless?from=pagser"
		},
		{
			"Names": [
				"vuejs",
				"vite"
			],
			"Description": "Experimental no-bundle dev server for Vue SFCs",
			"Stars": "1,573",
			"Repo": "https://github.com/vuejs/vite?from=pagser"
		}
	]
}
-------------

Colly Example

Work with colly:

p := pagser.New()


// On every a element which has href attribute call callback
collector.OnHTML("body", func(e *colly.HTMLElement) {
	//data parser model
	var data PageData
	//parse html data
	err := p.ParseSelection(&data, e.Dom)

})

Dependencies

github.com/PuerkitoBio/goquery
github.com/spf13/cast

Extensions:

github.com/mattn/godown
github.com/microcosm-cc/bluemonday

foolin/pagser

foolin

Reviews

Repository Details