colly

package module
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 Go to latest Published: Nov 12, 2017 License: Apache-2.0 Imports: 30 Imported by: 0

README

Colly

Lightning Fast and Elegant Scraping Framework for Gophers

Colly provides a clean interface to write any kind of crawler/scraper/spider.

With Colly you can easily extract structured data from websites, which can be used for a wide range of applications, like data mining, data processing or archiving.

GoDoc build status report card view examples test coverage

Features

  • Clean API
  • Fast (>1k request/sec on a single core)
  • Manages request delays and maximum concurrency per domain
  • Automatic cookie and session handling
  • Sync/async/parallel scraping
  • Caching
  • Automatic encoding of non-unicode responses
  • Robots.txt support

Example

func main() {
	c := colly.NewCollector()

	// Find and visit all links
	c.OnHTML("a[href]", func(e *colly.HTMLElement) {
		e.Request.Visit(e.Attr("href"))
	})

	c.OnRequest(func(r *colly.Request) {
		fmt.Println("Visiting", r.URL)
	})

	c.Visit("https://en.wikipedia.org/")
}

See examples folder for more detailed examples.

Installation

go get -u github.com/gocolly/colly/...

Bugs

Bugs or suggestions? Visit the issue tracker or join #colly on freenode

Other Projects Using Colly

Below is a list of public, open source projects that use Colly:

If you are using Colly in a project please send a pull request to add it to the list.

Documentation

Overview

Package colly implements a HTTP scraping framework

Index

Constants

This section is empty.

Variables

This section is empty.

Functions

func SanitizeFileName 

func SanitizeFileName(fileName string) string

SanitizeFileName replaces dangerous characters in a string so the return value can be used as a safe file name.

func UnmarshalHTML 

func UnmarshalHTML(v interface{}, s *goquery.Selection) error

UnmarshalHTML declaratively extracts text or attributes to a struct from HTML response using struct tags composed of css selectors. Allowed struct tags:

  • "selector" (required): CSS (goquery) selector of the desired data
  • "attr" (optional): Selects the matching element's attribute's value. Leave it blank or omit to get the text of the element.

Example struct declaration: 

type Nested struct {
	String  string   `selector:"div > p"`
   Classes []string `selector:"li" attr:"class"`
	Struct  *Nested  `selector:"div > div"`
}

Supported types: struct, *struct, string, []string

Types

type Collector 

type Collector struct {
	// UserAgent is the User-Agent string used by HTTP requests
	UserAgent string
	// MaxDepth limits the recursion depth of visited URLs.
	// Set it to 0 for infinite recursion (default).
	MaxDepth int
	// AllowedDomains is a domain whitelist.
	// Leave it blank to allow any domains to be visited
	AllowedDomains []string
	// DisallowedDomains is a domain blacklist.
	DisallowedDomains []string
	// URLFilters is a list of regular expressions which restricts
	// visiting URLs. If any of the rules matches to a URL the
	// request won't be stopped.
	// Leave it blank to allow any URLs to be visited
	URLFilters []*regexp.Regexp
	// AllowURLRevisit allows multiple downloads of the same URL
	AllowURLRevisit bool
	// MaxBodySize is the limit of the retrieved response body in bytes.
	// 0 means unlimited.
	// The default value for MaxBodySize is 10MB (10 * 1024 * 1024 bytes).
	MaxBodySize int
	// CacheDir specifies a location where GET requests are cached as files.
	// When it's not defined, caching is disabled.
	CacheDir string
	// IgnoreRobotsTxt allows the Collector to ignore any restrictions set by
	// the target host's robots.txt file.  See http://www.robotstxt.org/ for more
	// information.
	IgnoreRobotsTxt bool
	// contains filtered or unexported fields
}

Collector provides the scraper instance for a scraping job

func NewCollector 

func NewCollector() *Collector

NewCollector creates a new Collector instance with default configuration

func (*Collector) Appengine 

func (c *Collector) Appengine(req *http.Request)

Appengine will replace the Collector's backend http.Client With an Http.Client that is provided by appengine/urlfetch This function should be used when the scraper is initiated by a http.Request to Google App Engine

func (*Collector) Clone 

func (c *Collector) Clone() *Collector

Clone creates an exact copy of a Collector without callbacks. HTTP backend, robots.txt cache and cookie jar are shared between collectors.

func (*Collector) Cookies 

func (c *Collector) Cookies(URL string) []*http.Cookie

Cookies returns the cookies to send in a request for the given URL.

func (*Collector) DisableCookies 

func (c *Collector) DisableCookies()

DisableCookies turns off cookie handling

func (*Collector) Init 

func (c *Collector) Init()

Init initializes the Collector's private variables and sets default configuration for the Collector

func (*Collector) Limit 

func (c *Collector) Limit(rule *LimitRule) error

Limit adds a new LimitRule to the collector

func (*Collector) Limits 

func (c *Collector) Limits(rules []*LimitRule) error

Limits adds new LimitRules to the collector

func (*Collector) OnError 

func (c *Collector) OnError(f ErrorCallback)

OnError registers a function. Function will be executed if an error occurs during the HTTP request.

func (*Collector) OnHTML 

func (c *Collector) OnHTML(goquerySelector string, f HTMLCallback)

OnHTML registers a function. Function will be executed on every HTML element matched by the GoQuery Selector parameter. GoQuery Selector is a selector used by https://github.com/PuerkitoBio/goquery

func (*Collector) OnHTMLDetach 

func (c *Collector) OnHTMLDetach(goquerySelector string)

OnHTMLDetach deregister a function. Function will not be execute after detached

func (*Collector) OnRequest 

func (c *Collector) OnRequest(f RequestCallback)

OnRequest registers a function. Function will be executed on every request made by the Collector

func (*Collector) OnResponse 

func (c *Collector) OnResponse(f ResponseCallback)

OnResponse registers a function. Function will be executed on every response

func (*Collector) Post 

func (c *Collector) Post(URL string, requestData map[string]string) error

Post starts a collector job by creating a POST request. Post also calls the previously provided callbacks

func (*Collector) PostMultipart 

func (c *Collector) PostMultipart(URL string, requestData map[string][]byte) error

PostMultipart starts a collector job by creating a Multipart POST request with raw binary data. PostMultipart also calls the previously provided callbacks

func (*Collector) PostRaw 

func (c *Collector) PostRaw(URL string, requestData []byte) error

PostRaw starts a collector job by creating a POST request with raw binary data. Post also calls the previously provided callbacks

func (*Collector) Request 

func (c *Collector) Request(method, URL string, requestData io.Reader, ctx *Context, hdr http.Header) error

Request starts a collector job by creating a custom HTTP request where method, context, headers and request data can be specified. Set requestData, ctx, hdr parameters to nil if you don't want to use them. Valid methods:

  • "GET"
  • "POST"
  • "PUT"
  • "DELETE"
  • "PATCH"
  • "OPTIONS"

func (*Collector) SetCookieJar 

func (c *Collector) SetCookieJar(j *cookiejar.Jar)

SetCookieJar overrides the previously set cookie jar

func (*Collector) SetCookies 

func (c *Collector) SetCookies(URL string, cookies []*http.Cookie) error

SetCookies handles the receipt of the cookies in a reply for the given URL

func (*Collector) SetProxy 

func (c *Collector) SetProxy(proxyURL string) error

SetProxy sets a proxy for the collector. This overrides the previously used http.Transport if the type of the transport is not http.RoundTripper

func (*Collector) SetRequestTimeout 

func (c *Collector) SetRequestTimeout(timeout time.Duration)

SetRequestTimeout overrides the default timeout (10 seconds) for this collector

func (*Collector) String 

func (c *Collector) String() string

String is the text representation of the collector. It contains useful debug information about the collector's internals

func (*Collector) Visit 

func (c *Collector) Visit(URL string) error

Visit starts Collector's collecting job by creating a request to the URL specified in parameter. Visit also calls the previously provided callbacks

func (*Collector) Wait 

func (c *Collector) Wait()

Wait returns when the collector jobs are finished

func (*Collector) WithTransport 

func (c *Collector) WithTransport(transport http.RoundTripper)

WithTransport allows you to set a custom http.RoundTripper (transport)

type Context 

type Context struct {
	// contains filtered or unexported fields
}

Context provides a tiny layer for passing data between callbacks

func NewContext 

func NewContext() *Context

NewContext initializes a new Context instance

func (*Context) Get 

func (c *Context) Get(key string) string

Get retrieves a string value from Context. Get returns an empty string if key not found

func (*Context) GetAny 

func (c *Context) GetAny(key string) interface{}

GetAny retrieves a value from Context. GetAny returns nil if key not found

func (*Context) MarshalBinary 

func (c *Context) MarshalBinary() (_ []byte, _ error)

MarshalBinary encodes Context value This function is used by request caching

func (*Context) Put 

func (c *Context) Put(key string, value interface{})

Put stores a value of any type in Context

func (*Context) UnmarshalBinary 

func (c *Context) UnmarshalBinary(_ []byte) error

UnmarshalBinary decodes Context value to nil This function is used by request caching

type ErrorCallback 

type ErrorCallback func(*Response, error)

ErrorCallback is a type alias for OnError callback functions

type HTMLCallback 

type HTMLCallback func(*HTMLElement)

HTMLCallback is a type alias for OnHTML callback functions

type HTMLElement 

type HTMLElement struct {
	// Name is the name of the tag
	Name string
	Text string

	// Request is the request object of the element's HTML document
	Request *Request
	// Response is the Response object of the element's HTML document
	Response *Response
	// DOM is the goquery parsed DOM object of the page. DOM is relative
	// to the current HTMLElement
	DOM *goquery.Selection
	// contains filtered or unexported fields
}

HTMLElement is the representation of a HTML tag.

func (*HTMLElement) Attr 

func (h *HTMLElement) Attr(k string) string

Attr returns the selected attribute of a HTMLElement or empty string if no attribute found

func (*HTMLElement) ChildAttr 

func (h *HTMLElement) ChildAttr(goquerySelector, attrName string) string

ChildAttr returns the stripped text content of the first matching element's attribute.

func (*HTMLElement) ChildText 

func (h *HTMLElement) ChildText(goquerySelector string) string

ChildText returns the concatenated and stripped text content of the matching elements.

func (*HTMLElement) Unmarshal 

func (h *HTMLElement) Unmarshal(v interface{}) error

Unmarshal is a shorthand for colly.UnmarshalHTML

type LimitRule 

type LimitRule struct {
	// DomainRegexp is a regular expression to match against domains
	DomainRegexp string
	// DomainRegexp is a glob pattern to match against domains
	DomainGlob string
	// Delay is the duration to wait before creating a new request to the matching domains
	Delay time.Duration
	// Parallelism is the number of the maximum allowed concurrent requests of the matching domains
	Parallelism int
	// contains filtered or unexported fields
}

LimitRule provides connection restrictions for domains. Both DomainRegexp and DomainGlob can be used to specify the included domains patterns, but at least one is required. There can be two kind of limitations:

  • Parallelism: Set limit for the number of concurrent requests to matching domains
  • Delay: Wait specified amount of time between requests (parallelism is 1 in this case)

func (*LimitRule) Init 

func (r *LimitRule) Init() error

Init initializes the private members of LimitRule

func (*LimitRule) Match 

func (r *LimitRule) Match(domain string) bool

Match checks that the domain parameter triggers the rule

type Request 

type Request struct {
	// URL is the parsed URL of the HTTP request
	URL *url.URL
	// Headers contains the Request's HTTP headers
	Headers *http.Header
	// Ctx is a context between a Request and a Response
	Ctx *Context
	// Depth is the number of the parents of this request
	Depth int
	// contains filtered or unexported fields
}

Request is the representation of a HTTP request made by a Collector

func (*Request) AbsoluteURL 

func (r *Request) AbsoluteURL(u string) string

AbsoluteURL returns with the resolved absolute URL of an URL chunk. AbsoluteURL returns empty string if the URL chunk is a fragment or could not be parsed

func (*Request) Post 

func (r *Request) Post(URL string, requestData map[string]string) error

Post continues a collector job by creating a POST request and preserves the Context of the previous request. Post also calls the previously provided callbacks

func (*Request) PostMultipart 

func (r *Request) PostMultipart(URL string, requestData map[string][]byte) error

PostMultipart starts a collector job by creating a Multipart POST request with raw binary data. PostMultipart also calls the previously provided. callbacks

func (*Request) PostRaw 

func (r *Request) PostRaw(URL string, requestData []byte) error

PostRaw starts a collector job by creating a POST request with raw binary data. PostRaw preserves the Context of the previous request and calls the previously provided callbacks

func (*Request) Visit 

func (r *Request) Visit(URL string) error

Visit continues Collector's collecting job by creating a request and preserves the Context of the previous request. Visit also calls the previously provided callbacks

type RequestCallback 

type RequestCallback func(*Request)

RequestCallback is a type alias for OnRequest callback functions

type Response 

type Response struct {
	// StatusCode is the status code of the Response
	StatusCode int
	// Body is the content of the Response
	Body []byte
	// Ctx is a context between a Request and a Response
	Ctx *Context
	// Request is the Request object of the response
	Request *Request
	// Headers contains the Response's HTTP headers
	Headers *http.Header
}

Response is the representation of a HTTP response made by a Collector

func (*Response) FileName 

func (r *Response) FileName() string

FileName returns the sanitized file name parsed from "Content-Disposition" header or from URL

func (*Response) Save 

func (r *Response) Save(fileName string) error

Save writes response body to disk

type ResponseCallback 

type ResponseCallback func(*Response)

ResponseCallback is a type alias for OnResponse callback functions

Source Files

View all Source files

Directories

Path Synopsis
_examples
basic
coursera_courses
error_handling
google_groups
hackernews_comments
instagram
login
max_depth
multipart
openedx_courses
parallel
rate_limit
request_context
url_filter
xkcd_store
cmd
colly

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