Support creating a post

Plus fix Client post func and rename SubmittedPost to PostParams.

post.go

@@ -28,8 +28,8 @@ type (
 		Collection *Collection `json:"collection,omitempty"`
 	}
 
-	// SubmittedPost represents a new post for publishing or updating.
-	SubmittedPost struct {
+	// PostParams holds values for creating or updating a post.
+	PostParams struct {
 		Title    string  `json:"title"`
 		Content  string  `json:"body"`
 		Font     string  `json:"font"`
@@ -64,3 +64,26 @@ func (c *Client) GetPost(id string) (*Post, error) {
 	}
 	return p, nil
 }
+
+func (c *Client) CreatePost(sp *PostParams) (*Post, error) {
+	p := &Post{}
+	env, err := c.post("/posts", sp, p)
+	if err != nil {
+		return nil, err
+	}
+
+	var ok bool
+	if p, ok = env.Data.(*Post); !ok {
+		return nil, fmt.Errorf("Wrong data returned from API.")
+	}
+
+	status := env.Code
+	if status == http.StatusCreated {
+		return p, nil
+	} else if status == http.StatusBadRequest {
+		return nil, fmt.Errorf("Bad request: %s", env.ErrorMessage)
+	} else {
+		return nil, fmt.Errorf("Problem getting post: %s. %v\n", status, err)
+	}
+	return p, nil
+}

post_test.go

@@ -6,7 +6,21 @@ import (
 	"strings"
 )
 
-func TestGet(t *testing.T) {
+func TestCreatePost(t *testing.T) {
+	wac := NewClient("")
+	p, err := wac.CreatePost(&PostParams{
+		Title:   "Title!",
+		Content: "This is a post.",
+		Font:    "sans",
+	})
+	if err != nil {
+		t.Errorf("Post create failed: %v", err)
+	} else {
+		t.Logf("Post created: %+v", p)
+	}
+}
+
+func TestGetPost(t *testing.T) {
 	wac := NewClient("")
 
 	res, err := wac.GetPost("zekk5r9apum6p")

writeas.go

@@ -1,6 +1,7 @@
 package writeas
 
 import (
+	"bytes"
 	"encoding/json"
 	"errors"
 	"fmt"
@@ -43,8 +44,10 @@ func (c *Client) get(path string, r interface{}) (*impart.Envelope, error) {
 	return c.request(method, path, nil, r)
 }
 
-func (c *Client) post(path string, data io.Reader, r interface{}) (*impart.Envelope, error) {
-	return c.request("POST", path, data, r)
+func (c *Client) post(path string, data, r interface{}) (*impart.Envelope, error) {
+	b := new(bytes.Buffer)
+	json.NewEncoder(b).Encode(data)
+	return c.request("POST", path, b, r)
 }
 
 func (c *Client) request(method, path string, data io.Reader, result interface{}) (*impart.Envelope, error) {