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// Copyright 2018 Fedir RYKHTIK. All rights reserved. |
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// Use of this source code is governed by the GNU GPL 3.0 |
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// license that can be found in the LICENSE file. |
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// Package httpcache provides an interface to HTTP request static cache, |
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// |
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// Usage example : |
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// func main() { |
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// url := "https://api.github.com/repos/astaxie/beego/contributors" |
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// body := httpcache.MakeCachedHTTPRequest(url) |
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// jsonResp, linkHeader, _ := httpcache.ReadResp(body) |
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// fmt.Printf("%s\n%s", jsonResp, linkHeader) |
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// } |
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// |
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package httpcache |
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import ( |
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"bufio" |
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"bytes" |
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"crypto/sha256" |
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"encoding/hex" |
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"fmt" |
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"io/ioutil" |
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"log" |
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"net/http" |
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"net/http/httputil" |
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"os" |
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"time" |
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) |
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var cacheTTL = 3600 |
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var httpClient = &http.Client{Timeout: 10 * time.Second} |
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const dumpBody = true |
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// GetFilename gets encoded filename for cache usage |
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func GetFilename(url string) string { |
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encoder := sha256.New() |
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encoder.Write([]byte(url)) |
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return hex.EncodeToString(encoder.Sum(nil)) |
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} |
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// MakeHTTPRequest makes a non-cacheable request to the external URL |
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func MakeHTTPRequest(url string) ([]byte, int, error) { |
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req, err := http.NewRequest("GET", url, nil) |
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if err != nil { |
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log.Fatal("Cannont prepare the HTTP request", err) |
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} |
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if os.Getenv("GH_USR") != "" && os.Getenv("GH_PASS") != "" { |
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req.SetBasicAuth(os.Getenv("GH_USR"), os.Getenv("GH_PASS")) |
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} |
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resp, err := httpClient.Do(req) |
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if err != nil { |
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log.Fatal("Cannot process the HTTP request", err) |
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} |
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defer resp.Body.Close() |
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body, err := httputil.DumpResponse(resp, dumpBody) |
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if err != nil { |
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log.Fatal("Cannont dump the body of HTTP response", err) |
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} |
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return body, resp.StatusCode, err |
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} |
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func saveRespToFile(file string, resp []byte) { |
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err := ioutil.WriteFile(file, resp, 0644) |
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if err != nil { |
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panic(err) |
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} |
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} |
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func loadRespFromFile(file string) []byte { |
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resp, err := ioutil.ReadFile(file) |
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if err != nil { |
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panic(err) |
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} |
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return resp |
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} |
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// ReadResp : reads response from the cached HTTP query. |
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func ReadResp(fullResp []byte) ([]byte, string, error) { |
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r := bufio.NewReader(bytes.NewReader(fullResp)) |
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resp, err := http.ReadResponse(r, nil) |
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if err != nil { |
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log.Printf("%v\n%s", err, fullResp) |
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} |
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body, err := ioutil.ReadAll(resp.Body) |
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if err != nil { |
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log.Printf("%v\n%s", err, resp.Body) |
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} |
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linkHeader := resp.Header.Get("Link") |
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return body, linkHeader, err |
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} |
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// MakeCachedHTTPRequest makes a cacheable request to the external URL |
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// If the request was already made once, it will be not done again, |
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// but read from the file in temporary folder. |
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// Currently is was tested only for GET queries |
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func MakeCachedHTTPRequest(url string, tmpFolder string, debug bool) []byte { |
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var fullResp []byte |
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filename := GetFilename(url) |
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filepath := filename |
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if tmpFolder != "" { |
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filepath = tmpFolder + "/" + filename |
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} |
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if _, err := os.Stat(filepath); os.IsNotExist(err) { |
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if debug == true { |
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fmt.Println("HTTP query: " + url) |
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} |
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resp, statusCode, err := MakeHTTPRequest(url) |
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if err != nil { |
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panic(err) |
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} |
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if statusCode == 403 { |
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log.Fatalf("Looks like the rate limit is exceeded, please try again in 60 minutes. Or make a pull request with authentification feature.") |
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} else if statusCode == 202 { |
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log.Printf("Server need some time to prepare request. Trying again.") |
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time.Sleep(2 * time.Second) |
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return MakeCachedHTTPRequest(url, tmpFolder, debug) |
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} else if statusCode != 200 { |
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log.Fatalf("The status code of URL %s is not OK : %d", url, statusCode) |
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} |
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saveRespToFile(filepath, resp) |
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fullResp = loadRespFromFile(filepath) |
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} else { |
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if debug == true { |
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fmt.Println("Loaded results directly from: " + filepath) |
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} |
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fullResp = loadRespFromFile(filepath) |
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} |
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return fullResp |
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} |
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fedir /
ghstat
