| // +build ignore,OMIT |
| |
| // The server program issues Google search requests. It serves on port 8080. |
| // |
| // The /search endpoint accepts these query params: |
| // q=the Google search query |
| // |
| // For example, http://localhost:8080/search?q=golang serves the first |
| // few Google search results for "golang". |
| package main |
| |
| import ( |
| "encoding/json" |
| "fmt" |
| "html/template" |
| "log" |
| "net/http" |
| "net/url" |
| "time" |
| ) |
| |
| func main() { |
| http.HandleFunc("/search", handleSearch) // HL |
| fmt.Println("serving on http://localhost:8080/search") |
| log.Fatal(http.ListenAndServe("localhost:8080", nil)) |
| } |
| |
| // handleSearch handles URLs like "/search?q=golang" by running a |
| // Google search for "golang" and writing the results as HTML to w. |
| func handleSearch(w http.ResponseWriter, req *http.Request) { |
| log.Println("serving", req.URL) |
| |
| // Check the search query. |
| query := req.FormValue("q") // HL |
| if query == "" { |
| http.Error(w, `missing "q" URL parameter`, http.StatusBadRequest) |
| return |
| } |
| // ENDQUERY OMIT |
| |
| // Run the Google search. |
| start := time.Now() |
| results, err := Search(query) // HL |
| elapsed := time.Since(start) |
| if err != nil { |
| http.Error(w, err.Error(), http.StatusInternalServerError) |
| return |
| } |
| // ENDSEARCH OMIT |
| |
| // Render the results. |
| type templateData struct { |
| Results []Result |
| Elapsed time.Duration |
| } |
| if err := resultsTemplate.Execute(w, templateData{ // HL |
| Results: results, |
| Elapsed: elapsed, |
| }); err != nil { |
| log.Print(err) |
| return |
| } |
| // ENDRENDER OMIT |
| } |
| |
| // A Result contains the title and URL of a search result. |
| type Result struct { // HL |
| Title, URL string // HL |
| } // HL |
| |
| var resultsTemplate = template.Must(template.New("results").Parse(` |
| <html> |
| <head/> |
| <body> |
| <ol> |
| {{range .Results}} |
| <li>{{.Title}} - <a href="{{.URL}}">{{.URL}}</a></li> |
| {{end}} |
| </ol> |
| <p>{{len .Results}} results in {{.Elapsed}}</p> |
| </body> |
| </html> |
| `)) |
| |
| // Search sends query to Google search and returns the results. |
| func Search(query string) ([]Result, error) { |
| // Prepare the Google Search API request. |
| u, err := url.Parse("https://ajax.googleapis.com/ajax/services/search/web?v=1.0") |
| if err != nil { |
| return nil, err |
| } |
| q := u.Query() |
| q.Set("q", query) // HL |
| u.RawQuery = q.Encode() |
| |
| // Issue the HTTP request and handle the response. |
| resp, err := http.Get(u.String()) // HL |
| if err != nil { |
| return nil, err |
| } |
| defer resp.Body.Close() // HL |
| |
| // Parse the JSON search result. |
| // https://developers.google.com/web-search/docs/#fonje |
| var jsonResponse struct { |
| ResponseData struct { |
| Results []struct { |
| TitleNoFormatting, URL string |
| } |
| } |
| } |
| if err := json.NewDecoder(resp.Body).Decode(&jsonResponse); err != nil { // HL |
| return nil, err |
| } |
| |
| // Extract the Results from jsonResponse and return them. |
| var results []Result |
| for _, r := range jsonResponse.ResponseData.Results { // HL |
| results = append(results, Result{Title: r.TitleNoFormatting, URL: r.URL}) |
| } |
| return results, nil |
| } |
