Adding a new WithXML method (#402)

autorest/preparer.go

@@ -17,6 +17,7 @@ package autorest
 import (
 	"bytes"
 	"encoding/json"
+	"encoding/xml"
 	"fmt"
 	"io"
 	"io/ioutil"
@@ -377,6 +378,28 @@ func WithJSON(v interface{}) PrepareDecorator {
 	}
 }
 
+// WithXML returns a PrepareDecorator that encodes the data passed as XML into the body of the
+// request and sets the Content-Length header.
+func WithXML(v interface{}) PrepareDecorator {
+	return func(p Preparer) Preparer {
+		return PreparerFunc(func(r *http.Request) (*http.Request, error) {
+			r, err := p.Prepare(r)
+			if err == nil {
+				b, err := xml.Marshal(v)
+				if err == nil {
+					// we have to tack on an XML header
+					withHeader := xml.Header + string(b)
+					bytesWithHeader := []byte(withHeader)
+
+					r.ContentLength = int64(len(bytesWithHeader))
+					r.Body = ioutil.NopCloser(bytes.NewReader(bytesWithHeader))
+				}
+			}
+			return r, err
+		})
+	}
+}
+
 // WithPath returns a PrepareDecorator that adds the supplied path to the request URL. If the path
 // is absolute (that is, it begins with a "/"), it replaces the existing path.
 func WithPath(path string) PrepareDecorator {

autorest/preparer_test.go

@@ -238,6 +238,26 @@ func ExampleWithJSON() {
 	// Output: Request Body contains {"name":"Rob Pike","age":42}
 }
 
+// Create a request whose Body is the XML encoding of a structure
+func ExampleWithXML() {
+	t := mocks.T{Name: "Rob Pike", Age: 42}
+
+	r, err := Prepare(&http.Request{},
+		WithXML(&t))
+	if err != nil {
+		fmt.Printf("ERROR: %v\n", err)
+	}
+
+	b, err := ioutil.ReadAll(r.Body)
+	if err != nil {
+		fmt.Printf("ERROR: %v\n", err)
+	} else {
+		fmt.Printf("Request Body contains %s\n", string(b))
+	}
+	// Output: Request Body contains <?xml version="1.0" encoding="UTF-8"?>
+	// <T><Name>Rob Pike</Name><Age>42</Age></T>
+}
+
 // Create a request from a path with escaped parameters
 func ExampleWithEscapedPathParameters() {
 	params := map[string]interface{}{