Hulk did something

[bytom/vapor.git] / net / http / httpjson / io.go

diff --git a/net/http/httpjson/io.go b/net/http/httpjson/io.go
new file mode 100644 (file)
index 0000000..0d57d19
--- /dev/null
+++ b/net/http/httpjson/io.go
@@ -0,0 +1,59 @@
+package httpjson
+
+import (
+       "context"
+       "encoding/json"
+       "io"
+       "net/http"
+       "reflect"
+
+       log "github.com/sirupsen/logrus"
+       "github.com/vapor/errors"
+)
+
+const logModule = "httpjson"
+
+// ErrBadRequest indicates the user supplied malformed JSON input,
+// possibly including a datatype that doesn't match what we expected.
+var ErrBadRequest = errors.New("httpjson: bad request")
+
+// Read decodes a single JSON text from r into v.
+// The only error it returns is ErrBadRequest
+// (wrapped with the original error message as context).
+func Read(r io.Reader, v interface{}) error {
+       dec := json.NewDecoder(r)
+       dec.UseNumber()
+       err := dec.Decode(v)
+       if err != nil {
+               detail := errors.Detail(err)
+               if detail == "" || detail == err.Error() {
+                       detail = "check request parameters for missing and/or incorrect values"
+               }
+               return errors.WithDetail(ErrBadRequest, err.Error()+": "+detail)
+       }
+       return err
+}
+
+// Write sets the Content-Type header field to indicate
+// JSON data, writes the header using status,
+// then writes v to w.
+// It logs any error encountered during the write.
+func Write(ctx context.Context, w http.ResponseWriter, status int, v interface{}) {
+       w.Header().Set("Content-Type", "application/json; charset=utf-8")
+       w.WriteHeader(status)
+
+       err := json.NewEncoder(w).Encode(Array(v))
+       if err != nil {
+               log.WithFields(log.Fields{"module": logModule, "error": err}).Error("Error encountered during writing the Content-Type header using status")
+       }
+}
+
+// Array returns an empty JSON array if v is a nil slice,
+// so that it renders as "[]" rather than "null".
+// Otherwise, it returns v.
+func Array(v interface{}) interface{} {
+       if rv := reflect.ValueOf(v); rv.Kind() == reflect.Slice && rv.IsNil() {
+               v = []struct{}{}
+       }
+       return v
+}