Implement generic http query

frontend/ghost/client.go

@@ -1,8 +1,11 @@
 package ghost
 
 import (
+	"fmt"
+	"sync"
 	"time"
 
+	"github.com/mailru/easyjson"
 	"github.com/valyala/fasthttp"
 )
 // Ghost content data URIs:
@@ -18,6 +21,8 @@ type HTTPClient struct {
 	Secured      bool
 
 	client *fasthttp.HostClient
+
+	setupClientOnce sync.Once
 }
 
 // setupClient creates the default http client
@@ -31,3 +36,49 @@ func (g *HTTPClient) setupClient() {
 		DisablePathNormalizing:        true,
 	}
 }
+
+// doQuery does the method and unmarshals the result into the easyjson Unmarshaler
+func (g *HTTPClient) doQuery(method string, v easyjson.Unmarshaler, params ...QueryParam) (err error) {
+
+	g.setupClientOnce.Do(g.setupClient)
+
+	req := fasthttp.AcquireRequest()
+	res := fasthttp.AcquireResponse()
+	defer func() {
+		fasthttp.ReleaseResponse(res)
+		fasthttp.ReleaseRequest(req)
+	}()
+
+	uri := req.URI()
+	uri.SetHost(g.Addr)
+	uri.SetPath(method)
+	uri.QueryArgs().Add("key", g.ContentKey)
+	if g.client.IsTLS {
+		uri.SetScheme("https")
+	}
+
+	for _, param := range params {
+		param.Apply(&req.Header, uri.QueryArgs())
+	}
+
+	err = g.client.DoTimeout(req, res, g.QueryTimeout)
+	if err != nil {
+		return
+	}
+	if res.StatusCode() != fasthttp.StatusOK {
+		return fmt.Errorf("non OK status code: %d", res.StatusCode())
+	}
+
+	resBytes := res.Body()
+	if resBytes == nil && v == nil {
+		return fmt.Errorf("nothing to unmarshal")
+
+	}
+	if resBytes == nil {
+		return
+	}
+
+	err = easyjson.Unmarshal(resBytes, v)
+
+	return
+}