86 lines
2.3 KiB
Go
86 lines
2.3 KiB
Go
package externalip
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import (
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"io/ioutil"
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"log"
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"net"
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"net/http"
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"strings"
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"time"
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)
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// NewHTTPSource creates a HTTP Source object,
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// which can be used to request the (external) IP from.
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// The Default HTTP Client will be used if no client is given.
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func NewHTTPSource(url string) *HTTPSource {
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return &HTTPSource{
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url: url,
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}
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}
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// HTTPSource is the default source, to get the external IP from.
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// It does so by requesting the IP from a URL, via an HTTP GET Request.
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type HTTPSource struct {
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url string
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parser ContentParser
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}
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// ContentParser can be used to add a parser to an HTTPSource
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// to parse the raw content returned from a website, and return the IP.
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// Spacing before and after the IP will be trimmed by the Consensus.
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type ContentParser func(string) (string, error)
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// WithParser sets the parser value as the value to be used by this HTTPSource,
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// and returns the pointer to this source, to allow for chaining.
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func (s *HTTPSource) WithParser(parser ContentParser) *HTTPSource {
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s.parser = parser
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return s
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}
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// IP implements Source.IP
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func (s *HTTPSource) IP(timeout time.Duration, logger *log.Logger) (net.IP, error) {
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// Define the GET method with the correct url,
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// setting the User-Agent to our library
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req, err := http.NewRequest("GET", s.url, nil)
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if err != nil {
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logger.Printf("[ERROR] could not create a GET Request for %q: %v\n", s.url, err)
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return nil, err
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}
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req.Header.Set("User-Agent", "go-external-ip (github.com/glendc/go-external-ip)")
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client := &http.Client{Timeout: timeout}
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// Do the request and read the body for non-error results.
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resp, err := client.Do(req)
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if err != nil {
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logger.Printf("[ERROR] could not GET %q: %v\n", s.url, err)
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return nil, err
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}
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defer resp.Body.Close()
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bytes, err := ioutil.ReadAll(resp.Body)
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if err != nil {
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logger.Printf("[ERROR] could not read response from %q: %v\n", s.url, err)
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return nil, err
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}
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// optionally parse the content
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raw := string(bytes)
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if s.parser != nil {
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raw, err = s.parser(raw)
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if err != nil {
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logger.Printf("[ERROR] could not parse response from %q: %v\n", s.url, err)
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return nil, err
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}
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}
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// validate the IP
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externalIP := net.ParseIP(strings.TrimSpace(raw))
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if externalIP == nil {
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logger.Printf("[ERROR] %q returned an invalid IP: %v\n", s.url, err)
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return nil, InvalidIPError(raw)
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}
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// returned the parsed IP
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return externalIP, nil
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}
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