📰 blogger-feeds

Fully typed url builder, client and utilities for Blogger feeds

We ❤ Blogger

👨‍💻 Installation

Via npm

pnpm i blogger-feeds

Via cdn

<script type="module">
const { make } = await import("https://cdn.jsdelivr.net/npm/blogger-feeds@latest/core")
</script>

📦 Available exports

You can import just what you need to further tree-shake the package size

// Imports all at once
import * as BF from "blogger-feeds";

import { 
  make, // just the url builder function
} from "blogger-feeds/core";

import { 
  client, // just the client async generator
} from 'blogger-feeds/client';

import { 
  isoDate, // blogger-compatible date formatter
  merge, // merges blogger feeds urls or configs
  thumb, // remaps a blogger image url to a resized version
  ytimg, // remaps a youtube url to its default hq thumbnail
} from "blogger-feeds/helpers";

🤔 Why

This library serves a very specific use-case: read-only posts fetching on Blogger blogs, when the excellent Gapi + Blogger v3 api may be "overkill". In example when building a lightweight preact / alpinejs widget.

🔧 How it works

Url builder: make()

It's very a simple url builder function:

• builds on top of the native js URL interface
• takes a fully typed config object of blogger params
• validates them against Blogger conventions
• builds a native js URL to the requested resource
• explicits blogger defaults
• normalizes the url for cache consistency

Client generator: client()

An async function generator that:

• builds on top of the native fetch() api
• lazily loops over all posts starting from input
• reuses Blogger's own pagination features
• can be used in a handy for await ... of loop
• returns a fully-typed feed object (caveat)
• or a fully transparent error object

✔ Requirements

The url builder make() at the core of the package works by itself, enforcing parameter-level validation and expliciting blogger defaults for url consistency (helping caches work).

You may use the client() directly on a Blogger page with no additional setup. But in any other environment, since Blogger correctly enforces strict CORS headers, you are most likely to incur into cors issues. To avoid that:

1. Blogger must be setup with a custom domain
2. that domain should be sending proper CORS headers

To achieve this setup I am using Cloudflare's generous free plan, but any other solution is equally viable as long as it allows to enforce your own cors headers.

⚠ Caveats

1. Please note that the Feed object is not the fetched data, but a simplified representation exposing:

   • relevant meta data related to the request itself
   • a flattened susbet of relevant resource data

2. Should you need to access raw feeds data, you may prefer to avoid the client and directly fetch the url.

3. No sanitization is applied to any content returned from Blogger feeds. Please make sure to sanitize post.body html output using an html sanitizer library (like dom-purify, sanitize-html, js-xss...)

💪 Usage

//----------------------
//  import what you need
//----------------------

import { make, client } from "blogger-feeds";

//----------------------
//  build an url
//----------------------

const SinglePostUrl = make({
  // you may pass "blogger" to get the blogger.com equivalent
  blog: new URL("https://www.my-blogger.com"),
  
  postId: "1234567", // at least 7 digits
  
  // postId takes precedence over any other params
  // all the rest will be ignored
});

// null if invalid config
console.log(SinglePostUrl?.href);

const PagedPostsUrl = make({
  blog: new URL("https://www.my-blogger.com"),
  
  // never pass a valid postId 
  // when you need a paginated list
  
  // blogger's defaults will be added for consistency
  // "max-results": defaults to 25
  // "start-index": defaults to 1
  // "orderby": defaults to "published"
});

console.log(PagedPostsUrl?.href);

//----------------------
//  fetch a resource
//----------------------

// you may abort the client at any moment
const Aborter = new AbortController();

const DefaultClient = client({
  make: {
    // same config as make()
    blog: new URL("https://www.my-blogger.com"),
  },

  opt: { 
    // custom fetch options
    signal: Aborter.signal,
  },
  
  // cherry-pick meta or post props
  keep: ["href", "title", "image"],
});

for await (const feed of DefaultClient) {
  console.log(feed); // {meta: {...}, data: Array(25)} 
  // it loops as long as there are still posts to fetch 
  // take a look at meta.next
}

const PostClient = client({
  // reuse this url
  from: SinglePostUrl,

  make: {
    // with new params
    postId: '9876543',
  }
})

for await (const post of PostClient) {
  console.log(post); // {meta: {...}, data: Array(1)}
  // always 1 post in data array
}

Disclaimer

This library is very opinionated, it was built to consolidate code patterns from custom Blogger widgets currently employed in public-facing production blogs.

I remark that it is not meant to replace GAPI client, but it's just a different approach to fetch published posts in a read-only scenario, heavily inspired by Blogger's own dynamic templates.

The library is neither affiliated or approved by Google Blogger