source: code/trunk/engines/reverso.go@ 13

package engines

import (
        "bytes"
        "encoding/json"
        "fmt"
        "net/http"
)

// Reverso is an engine that fetches data from https://reverso.net.
type Reverso struct{}

func (_ *Reverso) InternalName() string { return "reverso" }

func (_ *Reverso) DisplayName() string { return "Reverso" }

var reversoLangs = []Language{
        {Name: "Arabic", Code: "ara"},
        {Name: "Chinese (Simplified)", Code: "chi"}, // marketed as just "Chinese"
        {Name: "Czech", Code: "cze"},
        {Name: "Danish", Code: "dan"},
        {Name: "Dutch", Code: "dut"},
        {Name: "English", Code: "eng"},
        {Name: "French", Code: "fra"},
        {Name: "German", Code: "ger"},
        {Name: "Hebrew", Code: "heb"},
        {Name: "Hindi", Code: "hin"},
        {Name: "Hungarian", Code: "hun"},
        {Name: "Italian", Code: "ita"},
        {Name: "Japanese", Code: "jpn"},
        {Name: "Korean", Code: "kor"},
        {Name: "Persian", Code: "per"},
        {Name: "Polish", Code: "pol"},
        {Name: "Portuguese", Code: "por"},
        {Name: "Romanian", Code: "rum"},
        {Name: "Russian", Code: "rus"},
        {Name: "Slovak", Code: "slo"},
        {Name: "Spanish", Code: "spa"},
        {Name: "Swedish", Code: "swe"},
        {Name: "Thai", Code: "tha"},
        {Name: "Turkish", Code: "tur"},
        {Name: "Ukrainian", Code: "ukr"},
}

func (_ *Reverso) SourceLanguages() ([]Language, error) { return reversoLangs, nil }

func (_ *Reverso) TargetLanguages() ([]Language, error) { return reversoLangs, nil }

func (_ *Reverso) SupportsAutodetect() bool { return true }

type reversoAPIResponse struct {
        LanguageDetection struct {
                DetectedLanguage string `json:"detectedLanguage"`
        } `json:"languageDetection"`
        Translation []string `json:"translation"`
}

func (e *Reverso) callAPI(text string, from, to Language) (reversoAPIResponse, error) {
        // `contextResults` must be false for language detection
        formData := map[string]interface{}{
                "format": "text",
                "from":   from.Code,
                "to":     to.Code,
                "input":  text,
                "options": map[string]interface{}{
                        "sentenceSplitter":  false,
                        "origin":            "translation.web",
                        "contextResults":    false,
                        "languageDetection": true,
                },
        }

        formDataJSON, err := json.Marshal(formData)

        if err != nil {
                return reversoAPIResponse{}, err
        }

        request, err := http.NewRequest("POST", "https://api.reverso.net/translate/v1/translation", bytes.NewBuffer(formDataJSON))

        if err != nil {
                return reversoAPIResponse{}, err
        }

        request.Header.Set("Content-Type", "application/json")
        // Returns 403 with empty or no user agent.
        request.Header.Set("User-Agent", "Mozilla/5.0 (Windows NT 10.0; rv:110.0) Gecko/20100101 Firefox/110.0")

        client := &http.Client{}

        response, err := client.Do(request)

        if err != nil {
                return reversoAPIResponse{}, err
        }

        defer response.Body.Close()

        if response.StatusCode != 200 {
                return reversoAPIResponse{}, fmt.Errorf("got status code %d from Reverso API", response.StatusCode)
        }

        var result reversoAPIResponse

        if err := json.NewDecoder(response.Body).Decode(&result); err != nil {
                return reversoAPIResponse{}, err
        }

        return result, nil
}

func (e *Reverso) DetectLanguage(text string) (Language, error) {
        // Any language pair works here, does not affect result
        r, err := e.callAPI(text, reversoLangs[0], reversoLangs[1])

        if err != nil {
                return Language{}, err
        }

        langCode := r.LanguageDetection.DetectedLanguage

        for _, lang := range reversoLangs {
                if lang.Code == langCode {
                        return lang, nil
                }
        }

        return Language{}, fmt.Errorf("language code \"%s\" is not in Reverso's language list", langCode)
}

func (e *Reverso) Translate(text string, from, to Language) (TranslationResult, error) {
        if from.Code == "auto" {
                from_, err := e.DetectLanguage(text)

                if err != nil {
                        return TranslationResult{}, err
                }

                from = from_
        }

        var translation string

        if from == to {
                translation = text
        } else {
                r, err := e.callAPI(text, from, to)

                if err != nil {
                        return TranslationResult{}, err
                }

                translation = r.Translation[0]
        }

        return TranslationResult{
                SourceLanguage: from,
                TranslatedText: translation,
        }, nil
}