request.go

package colly

import (
	"bytes"
	"io"
	"net/http"
	"net/url"
	"strings"
)

// Request is the representation of a HTTP request made by a Collector
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 the request
	Depth int
	// Method is the HTTP method of the request
	Method string
	// Body is the request body which is used on POST/PUT requests
	Body io.Reader
	// ID is the Unique identifier of the request
	ID        uint32
	collector *Collector
}

// 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 (r *Request) AbsoluteURL(u string) string {
	if strings.HasPrefix(u, "#") {
		return ""
	}
	absURL, err := r.URL.Parse(u)
	if err != nil {
		return ""
	}
	absURL.Fragment = ""
	if absURL.Scheme == "//" {
		absURL.Scheme = r.URL.Scheme
	}
	return absURL.String()
}

// 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
func (r *Request) Visit(URL string) error {
	return r.collector.scrape(r.AbsoluteURL(URL), "GET", r.Depth+1, nil, r.Ctx, nil, true)
}

// 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 (r *Request) Post(URL string, requestData map[string]string) error {
	return r.collector.scrape(r.AbsoluteURL(URL), "POST", r.Depth+1, createFormReader(requestData), r.Ctx, nil, true)
}

// 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 (r *Request) PostRaw(URL string, requestData []byte) error {
	return r.collector.scrape(r.AbsoluteURL(URL), "POST", r.Depth+1, bytes.NewReader(requestData), r.Ctx, nil, true)
}

// PostMultipart starts a collector job by creating a Multipart POST request
// with raw binary data.  PostMultipart also calls the previously provided.
// callbacks
func (r *Request) PostMultipart(URL string, requestData map[string][]byte) error {
	boundary := randomBoundary()
	hdr := http.Header{}
	hdr.Set("Content-Type", "multipart/form-data; boundary="+boundary)
	hdr.Set("User-Agent", r.collector.UserAgent)
	return r.collector.scrape(r.AbsoluteURL(URL), "POST", r.Depth+1, createMultipartReader(boundary, requestData), r.Ctx, hdr, true)
}

// Retry submits HTTP request again with the same parameters
func (r *Request) Retry() error {
	return r.collector.scrape(r.URL.String(), r.Method, r.Depth, r.Body, r.Ctx, *r.Headers, false)
}