3 Feed reader users should be able to subscribe to the blog
7 As of this writing, the blog is served as HTML which is appropriate for
8 web browsers but maybe not for other mechanisms like feed readers.
10 Feed readers have different formats that they support:
11 * h-feed is a microformat built into the page
12 * rss and atom are XML based publishing formats
13 * JSON feed is a JSON based publishing format
14 * rss 3.0 is a text based pblishing format :P
16 Currently the blog contains a single generator function that copies
17 assets and generates HTML out of markdown files. This is good enough for
18 the current setup, but if it were to generate more it would get messy
21 Given the constraints listed below, some formats are not recommended:
22 * RSS 3.0 is not a good candidate at the moment as it would require
23 us to parse the markdown to extract the title.
24 * Atom would work, however, given the requirement for an id, title, and
25 date this would require more effort than a more lenient format.
26 * RSS 2.0 fits the constraints as we wouldn't need to specify anything
28 * JSON Feed would work, however given the requirement for an id, thtis
29 would require more effort than a more lenient format.
31 It is unclear whether the current constraints are good enough for feed
32 readers. If this causes issues, it's likely we will have to include date,
33 id or title as required in the other formats.
35 After reviewing the functionality of existing readers, it has been found
36 that an id and publication date would be needed for readers to behave
37 correctly. This means that ATOM and JSON Feed would be equally valid
38 as solutions than RSS 2.0
40 The current generator function depends on knowing a source for the post
41 being generated, and a target on where the assets will be placed.
45 Given we serve the blog in a feed reader friendly format, users will be able to subscribe.
49 Given I add the blog to a feed reader service like Reeder or Feedly, I will be able to see the entries.
50 Given I add a new entry to the blog, the entries will be updated.
54 * We can generate a valid feed with just the entries themselves and the existing
56 * We can: Validated by generating an example file.
57 * Including just a list of items with the whole content is good enough for
59 * We can't: It seems like we'll require at least a guid. The old reader
60 behaves correctly with just the guid. It's unclear whether feedly
61 does since it has caching. Will leave grok running.
62 * It isn't required to link back, and we can include the whole text.
63 * This is correct, however it might make sense to just link to the
68 * We won't be parsing the markdown to generate feed items.
69 * We won't be adding any sort of frontmatter to the entries.
70 * The blog will remain ephemeral, and we won't introduce permalinks.
71 * We won't have configurable templating or options to add/remove
76 We will add a new step in the creation process to create metadata for the
77 post that will allow each post to be uniquely identified, as well as
78 having a publish date related to them.
80 We will split the current generator function into generators, and create
81 a new generator that will generate an RSS 2.0 file
86 ╔══════════════════════╗
87 ║ When Adding a Post ║
88 ╚══════════════════════╝
89 ┌───────────────┐ ┌───────────────┐
91 ┌────────────────▶│ writeMetadata │─────────▶│ Metadata File │
93 │ └───────────────┘ └───────────────┘
96 │ ╔════════════════════════╗
97 │ ║ When Generating Output ║
98 │ ╚════════════════════════╝
99 │ ┌─────────────────┐ ┌───────────────┐
101 │ ┌─────▶│ StaticGenerator │───────▶│ Static Assets │
103 │ │ └─────────────────┘ └───────────────┘
104 ┌───────┐ │ ┌───────────────┐ ┌───────────┐
106 │ Blog │──────┼─────▶│ HTMLGenerator │─────────▶│ HTML File │
108 └───────┘ │ └───────────────┘ └───────────┘
109 │ ┌──────────────┐ ┌──────────┐
111 └─────▶│ RSSGenerator │──────────▶│ RSS File │
113 └──────────────┘ └──────────┘
116 # Theory of Operation
118 ## When Adding a Post
120 When the add function of the blog is triggered, it will shift the posts
121 as it currently does and then will generate a new unique ID and take the
122 current timestamp. This will be saved in a JSON file in the output
123 directory called "metadata.json"
125 ## When Generating Output
127 When the generate function of the blog is triggered, it will iterate
128 over every post. For each of them it will parse the markdown content,
129 and the metadata, creating an object of type `tPost` and pushing it
132 Next, it will iterate from a list of generator functions and call them
133 with the source and target directories, and an array containing the `tPost`
134 objects. Each generator function will do its work, throwing an exception
135 if they encounter an error.
137 When the static generator is called, it will remove the current assets
138 directory in the target directory, and recursively copy the assets from
139 the source directory.
141 When the HTML generator is called, it will parse an `html` template, using
142 the posts as the context, and will place the resulting file in the target
145 When the RSS generator is called, it will parse an `rss` template, using
146 the posts as the context, and will place the resulting file in the target
149 # Technical Specification
151 ## The Post Data Structure
153 This spec introduces a data structure to help generate output.
157 +html <String> // The markup of the post
158 +publishedOn <Number> // The timestamp when this post was added
159 +id <String> // The Unique ID for this post
162 Given that posts won't come in at a high enough rate, and that the
163 purpouse is only to help feed readers identify each unique piece of
164 content, for this version the `id` will be the same number as the
167 ## The Generator Interface
169 Every generator must implement this interface in order to work with
172 * Generators MUST be a function
173 * Generators SHOULD read the source, destination, and posts parameters to
175 * Generators MUST NOT write anything into the source directory
176 * Generators MUST return a promise
177 * Generators SHOULD NOT resolve the promise with any information, as it will
179 * Generators MUST throw exceptions if they encounter an unrecoverable error
182 IGenerator(source<String>, destination<String>, posts<Array<String>>) => Promise
189 This generator will have the logic to move static assets around. It will
190 re-use the current asset logic in the `#_generate` method in Blog.
193 StaticGenerator <IGenerator>
198 This generator will have the logic to generate an HTML file. It will
199 re-use the current HTML logic in the `#_generate` method in Blog.
202 HTMLGenerator <IGenerator>
207 This generator will have the logic to generate an RSS file. It will
208 re-use the current HTML logic in the `#_generate` method in Blog,
209 however, instead of using the `index.html` template it will use a
210 `feed.xml` template that generates a valid RSS 2.0 feed document.
213 RSSGenerator <IGenerator>
216 ## Modifications to existing parts of the code
218 The `#_generate` function will be modified so it will now parse the
219 post markdown, and then iterate over the generators, calling them
220 so they create the appropriatet files.
224 Given we're only processing 3 blog posts, and this is a compile time
225 activity and not runtime, there are no recommended metrics in terms
226 of file throughput performance or runtime performance.
228 This should change if this would ever handle a higher volume, or would
229 be expected to run this process runtime.
231 ## Furhter Improvements
233 It's recommended to eventually put more effort in assigning a unique ID
234 to each post so we can use more feed formats.
236 For more compatibility and future proofing, the same solution for
237 RSS could be used to generate other feed formats, just adding
240 This same solution could be extended to serve the blog in different formats
241 (eg. a .txt that is easy to read in terminals)
git.r.bdr.sh / rbdr / blog / blob