Merge pull request #6 from ButterCMS/feat/add-preview-param

feat: preview mode for ButterCMS

README.md

@@ -61,6 +61,16 @@ ButterCMS.SearchPosts("query", params)
 
 To include this package in your Go code, simply use `import "ButterCMS"` at the top of your file
 
+### Preview mode
+
+Preview mode can be used to setup a staging website for previewing content fields or for testing content during localdevelopment. To fetch content from preview mode call `ButterCMS.SetPreviewMode` with `true` input:
+
+```go
+package main
+...
+ButterCMS.SetPreviewMode(true)
+```
+
 ## Example Usage
 
 ```go

buttercms.go

@@ -1,17 +1,19 @@
 package ButterCMS
 
 import (
-	"strings"
 	"encoding/json"
 	"errors"
 	"io/ioutil"
 	"net/http"
+	"strings"
 )
 
 var authToken string
 
+var preview bool
+
 const (
-	VERSION = "2.3.0"
+	VERSION      = "2.3.0"
 	API_ROOT_URL = "https://api.buttercms.com/v2/"
 )
 
@@ -30,6 +32,11 @@ func getRequest(path string, params map[string]string) ([]byte, error) {
 	for k := range params {
 		q.Add(k, params[k])
 	}
+
+	if preview {
+		q.Add("preview", "1")
+	}
+
 	req.URL.RawQuery = q.Encode()
 
 	resp, err := client.Do(req)
@@ -56,6 +63,10 @@ func SetAuthToken(token string) {
 	authToken = token
 }
 
+func SetPreviewMode(inPreview bool) {
+	preview = inPreview
+}
+
 ///////////
 // Feed
 ///////////