update gpt2 interface

plugins/gpt2/gpt2.go

@@ -1,10 +1,10 @@
 package gpt2
 
 import (
+	"bytes"
+	"encoding/json"
 	"fmt"
-	"io/ioutil"
 	"net/http"
-	"net/url"
 	"strings"
 
 	"github.com/velour/catbase/bot"
@@ -54,24 +54,46 @@ func (p *GPT2Plugin) help(c bot.Connector, kind bot.Kind, message msg.Message, a
 
 const separator = "<|endoftext|>"
 
-func (p *GPT2Plugin) getGPTText(input string) (string, error) {
-	serviceURI := p.c.Get("gpt.service", "")
+func (p *GPT2Plugin) getGPTText(prefix string) (string, error) {
+	serviceURI := p.c.Get("gpt2.service", "")
+
 	if serviceURI == "" {
 		return "", fmt.Errorf("cannot contact GPT2 service")
 	}
-	values := url.Values{}
-	values.Add("text", input)
-	resp, err := http.PostForm(serviceURI, values)
+
+	args := struct {
+		Prefix      string  `json:"prefix"`
+		Length      int     `json:"length"`
+		Temperature float64 `json:"temperature"`
+		TopP        float64 `json:"top_p"`
+		TopK        float64 `json:"top_k"`
+	}{
+		Prefix:      prefix,
+		Length:      p.c.GetInt("gpt2.length", 50),
+		Temperature: p.c.GetFloat64("gpt2.temperature", 0.7),
+		TopK:        p.c.GetFloat64("gpt2.topk", 0),
+		TopP:        p.c.GetFloat64("gpt2.topp", 0),
+	}
+
+	values, _ := json.Marshal(args)
+
+	resp, err := http.Post(serviceURI, "application/json", bytes.NewBuffer(values))
 	if err != nil {
 		return "", fmt.Errorf("error retrieving GPT2 response: %s", err)
 	}
-	body, err := ioutil.ReadAll(resp.Body)
 	if err != nil {
 		return "", fmt.Errorf("error reading GPT2 response: %s", err)
 	}
-	resp.Body.Close()
-	txt := p.cleanup(input + string(body))
-	return txt, nil
+	defer resp.Body.Close()
+	dec := json.NewDecoder(resp.Body)
+	output := struct {
+		Text string `json:"text"`
+	}{}
+	err = dec.Decode(&output)
+	if err != nil {
+		return "", err
+	}
+	return p.cleanup(output.Text), nil
 }
 
 func (p *GPT2Plugin) cleanup(txt string) string {