Blogger Go Cli
2020-03-14T21:16:00Z
Introduction
We will be creating a commandLine utility in Go to upload a post in Google blogger.
Account Preparation
- You need to have a google account (gmail) (Paid account NOT required).
- Once you have a google account, Login to https://console.developers.google.com/apis/credentials and create a new Project here.
- Click on Dashboard on left hand column, and click on `+ ENABLE APIS AND SERVICES`.
- Type in blogger in search bar, and select Blogger API v3 and then click ENABLE.`
- Click on OAuth consent screen on left hand column, and select User Type to External and click CREATE.
- On next screen type in Application Name as Blogger CLI (It can be any string).
- Click on Add Scope and select both the Blogger API v3 options and click ADD and click Save.
- Click on Credentials on the left hand side and you will be presented with following two options of creating credentials for Blogger API.
- API Keys
- OAuth 2.0 Client IDs
- Service Accounts
- Click on `+ CREATE CREDENTAILSon the top and selectOAuth Client ID` from drop down menu.
- Select Application Type to other.
- Type in Name to CLI Utility (it can be any string) and click create.
- You will see an entry with name CLI Utility under OAuth 2.0 Client IDs.
- Download the credential files by clicking on a down arrow button.
- This will be a json file and we need it to authenticate it with google OAuth2.0 services.
- Login to blogger site https://www.blogger.com
- Sign-in to blogger.
- Enter a display name you like.
- Create a NEW BLOG and give it a name you like in Ttile
- Type in address. It has to be a unique e.g somethingrandom23455.blogspot.com and click create blog
- On next screen, look at the address bar of browser, it will be like https://www.blogger.com/blogger.g?blogID=3342324243435#allposts
- Note down blog ID (a string after blogID=, excluding #allposts) in above URL. We need this ID to put in Go script.
Go development environment creation
I am using following Go version.
Setup following Go development directory structure.
Populate BloggerCli/go-cli/createAndActivateGoWorkSpace.sh with following contents
#! /bin/bash
# current directory is workspace
WORKSPACE=$(pwd)
cd "$WORKSPACE"
mkdir -p src bin pkg
export GOPATH=$WORKSPACE
export GOBIN=$WORKSPACE/binCreate directory structure
Install required libraries.
Copy credential file.
Copy above downloaded credential json file in BloggerCli/go-cli/src/blogger folder and rename it to OAuth2.0_secret.json.
Note: You can rename it any name
Create Go file BloggerCli/go-cli/src/blogger/bloggerCli.go file with following contents.
package main
/*
https://pkg.go.dev/google.golang.org/api/blogger/v3?tab=doc
https://godoc.org/google.golang.org/api/option
https://pkg.go.dev/golang.org/x/oauth2/google?tab=doc
https://pkg.go.dev/golang.org/x/oauth2?tab=doc#Config.AuthCodeURL
*/
import (
"context"
"flag"
"fmt"
"io/ioutil"
"log"
"os"
"strings"
"golang.org/x/oauth2"
"golang.org/x/oauth2/google"
"google.golang.org/api/blogger/v3"
"google.golang.org/api/option"
)
func checkErrorAndExit(err error) {
if err != nil {
log.Fatal(err)
}
}
func printNoOfPosts(postsService *blogger.PostsService, BlogID string) {
postListCall := postsService.List(BlogID).MaxResults(500)
postList, err := postListCall.Do()
checkErrorAndExit(err)
fmt.Printf("Total posts in this blog: %d\n", len(postList.Items))
}
func getBloggerClient() *blogger.Service {
ctx := context.Background()
contents, err := ioutil.ReadFile("OAuth2.0_secret.json")
checkErrorAndExit(err)
conf, err := google.ConfigFromJSON(contents, blogger.BloggerScope)
checkErrorAndExit(err)
url := conf.AuthCodeURL("state")
fmt.Println("Visit the following URL for the auth dialog:")
fmt.Printf("\n%v\n", url)
var code string
fmt.Printf("\nEnter the code obtained from above here: ")
fmt.Scanln(&code)
token, err := conf.Exchange(oauth2.NoContext, code)
checkErrorAndExit(err)
bloggerService, err := blogger.NewService(ctx, option.WithTokenSource(conf.TokenSource(ctx, token)))
checkErrorAndExit(err)
return bloggerService
}
func checkMandatoryArguments(args []*string) {
allArgsExists := true
for _, val := range args {
if len(*val) == 0 {
allArgsExists = allArgsExists && false
} else {
allArgsExists = allArgsExists && true
}
}
if !allArgsExists {
flag.PrintDefaults()
os.Exit(2)
}
}
func createNewPost(title *string, labels *string, fileToUpload *string) *blogger.Post {
labelsSlice := strings.Split(*labels, ",")
contents, err := ioutil.ReadFile(*fileToUpload)
checkErrorAndExit(err)
newPost := blogger.Post{}
if len(*labels) == 0 {
newPost = blogger.Post{
Content: string(contents),
Title: *title,
}
} else {
newPost = blogger.Post{
Content: string(contents),
Labels: labelsSlice,
Title: *title,
}
}
return &newPost
}
func insertAPost(title *string, labels *string, fileToUpload *string, BlogID string, postsService *blogger.PostsService) {
fmt.Println("============= Inserting a new Post ===============")
newPost := createNewPost(title, labels, fileToUpload)
postInsertCall := postsService.Insert(BlogID, newPost)
post, err := postInsertCall.Do()
checkErrorAndExit(err)
fmt.Println("A new post added to Blog with following details")
fmt.Printf("Title: %s\nPostID: %s\n", post.Title, post.Id)
fmt.Println("=================================================")
printNoOfPosts(postsService, BlogID)
}
func updateAPost(title *string, labels *string, fileToUpload *string, BlogID string, postsService *blogger.PostsService, postID string) {
fmt.Println("============= updating a Post ===============")
// Search post from Title if postID not specified.
if len(postID) == 0 {
postsSearchCall := postsService.Search(BlogID, *title)
postsList, err := postsSearchCall.Do()
checkErrorAndExit(err)
if len(postsList.Items) > 1 {
fmt.Printf("Following multiple posts found for title = %s\n", *title)
for _, post := range postsList.Items {
fmt.Println(post.Title)
}
log.Fatal("\n\nERROR: Not updating post. Title must identify a single post only. Try specifying PostID")
} else {
postID = postsList.Items[0].Id
}
}
newPost := createNewPost(title, labels, fileToUpload)
postsPatchCall := postsService.Patch(BlogID, postID, newPost)
post, err := postsPatchCall.Do()
checkErrorAndExit(err)
fmt.Println("Following post has been updated in Blog with following details")
fmt.Printf("Title: %s\nPostID: %s\n", post.Title, post.Id)
fmt.Println("=================================================")
printNoOfPosts(postsService, BlogID)
}
func main() {
fileToUpload := flag.String("f", "", "html file to upload (mandatory)")
title := flag.String("t", "", "Post title (mandatory)")
blogid := flag.String("b", "", "Blod ID (mandatory)")
labels := flag.String("l", "", "comma separated list of labels (optional)")
modify := flag.Bool("m", false, "Modify a post contents (optional: modifies post in mentioned in -t )")
postID := flag.String("p", "", "post ID (optional: To be specified when updating a post)")
flag.Parse()
if flag.NFlag() == 0 {
flag.PrintDefaults()
os.Exit(1)
}
mandatoryArgs := []*string{fileToUpload, title, blogid}
checkMandatoryArguments(mandatoryArgs)
BlogID := *blogid
PostID := *postID
bloggerService := getBloggerClient()
postsService := bloggerService.Posts
printNoOfPosts(postsService, BlogID)
if !*modify {
insertAPost(title, labels, fileToUpload, BlogID, postsService)
} else {
updateAPost(title, labels, fileToUpload, BlogID, postsService, PostID)
}
}Create a test file to be uploaded.
Note: You can create an HTML file as well.
Run the script
Create a New Post
$ cd BloggerCli/go-cli/src/blogger
$ go run bloggerCli.go -b 232343232322 -f sometext.txt -t "A new Post" -l "label1,label2"
Visit the URL for the auth dialog: https://accounts.google.com/o/oauth2/auth?client_id=99999999-ccc55566666iiioo999ddd.apps.googleusercontent.com&redirect_uri=urn%3Aietf%3Awg%3Aoauth%3A2.0%3Aoob&response_type=code&scope=https%3A%2F%2Fwww.googleapis.com%2Fauth%2Fblogger&state=state
Enter the code obtained from above here: 9/rf7hM-sds98JnHgsdK90OiYhsss790NHdsaDs
Total posts in this blog: 51
============= Inserting a new Post ===============
A new post added to Blog with following details
Title: A new Post
PostID: 2344555555555999
=================================================
Total posts in this blog: 52Update a Post
$ cd BloggerCli/go-cli/src/blogger
$ go run bloggerCli.go -b 232343232322 -f sometext.txt -t "Multiple Vms Vagrantfile" -m
Visit the URL for the auth dialog: https://accounts.google.com/o/oauth2/auth?client_id=99999999-ccc55566666iiioo999ddd.apps.googleusercontent.com&redirect_uri=urn%3Aietf%3Awg%3Aoauth%3A2.0%3Aoob&response_type=code&scope=https%3A%2F%2Fwww.googleapis.com%2Fauth%2Fblogger&state=state
Enter the code obtained from above here: 9/rf7hM-sds98JnHgsdK90OiYhsss790NHdsaDs
Total posts in this blog: 51
============= updating a Post ===============
Following post has been updated in Blog with following details
Title: Multiple Vms Vagrantfile
PostID: 334556669992323
=================================================
Total posts in this blog: 51Note: You need to open the URL mentioned in the above output in a browser and authorize the request. This will return a code that need to enter above.
References used
- https://pkg.go.dev/google.golang.org/api/blogger/v3?tab=doc
- https://godoc.org/google.golang.org/api/option
- https://pkg.go.dev/golang.org/x/oauth2/google?tab=doc
- https://pkg.go.dev/golang.org/x/oauth2?tab=doc#Config.AuthCodeURL