◊(Local Yarn Code "Check-in [d3755213]")

   [published            string/f]
   [updated              string/f]
   [author               string/f]
   [conceal              string/f]
   [series-page          symbol/f]
   [noun-singular        string/f]
   [note-count           integer/f]
   [doc-html             string/f]
   [content-html             string/f]
   [disposition          string/f]
   [disp-html-anchor     string/f]
   [listing-full-html    string/f]   ; full content but without notes
   [listing-excerpt-html string/f]   ; Not used for now
   [listing-short-html   string/f])) ; Date and title only

(define-schema cache:note #:table "notes"

   [entry       string/f]
   [subentry    string/f]
   [page        symbol/f]
   [html-anchor string/f]))

(define-schema listing
  #:virtual
  ([html        string/f]
   [published   date/f]
   [series-page symbol/f]))
  ([path        string/f]
   [title       string/f]
   [author      string/f]
   [published   string/f]
   [updated     string/f]
   [html        string/f]))

(define (init-cache-db!)
  (create-table! (cache-conn) 'cache:article)
  (create-table! (cache-conn) 'cache:note)
  (create-table! (cache-conn) 'cache:series)
  (create-table! (cache-conn) 'cache:index-entry))

;; Needed to "parameterize" column names
;; see https://github.com/Bogdanp/deta/issues/14#issuecomment-573344928
(require (prefix-in ast: deta/private/ast))

;; Builds a query to fetch articles
(define (articles type #:series [s #t] #:limit [lim -1] #:order [ord 'desc])
  (define html-field (format "listing_~a_html" type))
  (define html-field
    (match type
      ['content "content_html"]
      [_ (format "listing_~a_html" type)]))
  (~> (from cache:article #:as a)
      (select (fragment (ast:as (ast:qualified "a" html-field) "html"))
      (select (as a.page path)
              (as a.title-plain title)
              a.author
              a.published
              a.series-page
              a.conceal)
              a.updated
              (fragment (ast:as (ast:qualified "a" html-field) "html")))
      (where-series s)
      (where-not-concealed)
      (limit ,lim)
      (order-by ([a.published ,ord]))
      (project-onto listing-schema)))

;; Builds a query that returns articles and notes intermingled chronologically
(define (articles+notes type #:series [s #t] #:limit [lim -1] #:order [ord 'desc])
  (define html-field (format "listing_~a_html" type))
  (define html-field
    (match type
      ['content "content_html"]
      [_ (format "listing_~a_html" type)]))
  (~> (from (subquery
             (~> (from cache:article #:as A)
                 (select (fragment (ast:as (ast:qualified "A" html-field) "html"))
                         A.published
                         A.series-page
                         A.conceal)
                 (select 
                  (as A.page path)
                  (as A.title-plain title)
                  A.author
                  A.published
                  A.updated
                  (fragment (ast:as (ast:qualified "A" html-field) "html"))
                  A.series-page
                  A.conceal)
                 (union
                  (~> (from cache:note #:as N)
                      (select (fragment (ast:as (ast:qualified "N" html-field) "html"))
                              N.published
                              N.series-page
                              N.conceal)))))
                      (select 
                       (as (array-concat N.page "#" N.html-anchor) path)
                       (as N.title-plain title)
                       N.author
                       N.published
                       (as "" updated) 
                       (fragment (ast:as (ast:qualified "N" html-field) "html"))
                       N.series-page
                       N.conceal)))))
            #:as a)
      (where-series s)
      (where-not-concealed)
      (limit ,lim)
      (order-by ([a.published ,ord]))
      (project-onto listing-schema)))

Returns the HTML bodies for the articles and/or notes returned by @racket[_listing-query] as a list
of strings. The @racket[_query] will usually be the result of a call to @racket[articles] or
@racket[articles+notes], but can be any custom query that projects onto the @racket[listing] schema
(see @racket[project-onto]).

}

@deftogether[(@defproc[(articles [type (or/c 'full 'excerpt 'short)]
@deftogether[(@defproc[(articles [type (or/c 'full 'excerpt 'short 'content)]
                                 [#:series series (or/c string? (listof string?) boolean?) #t]
                                 [#:limit limit integer? -1]
                                 [order stringish? 'desc]) query?]
              @defproc[(articles+notes [type (or/c 'full 'excerpt 'short)]
              @defproc[(articles+notes [type (or/c 'full 'excerpt 'short 'content)]
                                       [#:series series (or/c string? (listof string?) boolean?) #t]
                                       [#:limit limit integer? -1]
                                       [order stringish? 'desc]) query?])]{

Create a query that fetches either articles only, or articles and notes intermingled, respectively.
The results will be sorted by publish date according to @racket[_order] and optionally limited to
a particular series. Use the resulting query with the @racket[listing-htmls] or
@racket[fenced-listing] functions provided by this module, or with deta’s @racket[in-entities] if
you want to work with the @racket[listing] schema structs.

The @racket[_type] parameter specifies what version of the articles’ and notes’ HTML markup you
want. For HTML suitable for listing several articles and/or notes together on the same page, use
@racket['full] (the full content but not including @tech{notes}), @racket['excerpt] (like full but
abbreviated to only the excerpt if one was specified) or @racket['short] (date and title only). Use
@racket['content] to get the entire HTML content, including any notes but not including any header
or footer. (This is the option used in the RSS feed.)

If @racket[_series] expression evaluates to @racket[#f], articles will not be filtered by series. If
it evaluates to @racket[#t] (the default), articles will be filtered by those that specify the
current output of @racket[here-output-path] in their @tt{series_pagenode} column in the SQLite
cache. If a string or a symbol is supplied, articles will be filtered by those containing the result
of @racket[(format "series/~a.html" _series)] in their @tt{series_pagenode} column in the SQLite
cache. If a list of strings or symbols is provided, this @racket[format] operation will be applied
to each of its members and articles whose @tt{series_pagenode} column matches any of the resulting
values will be included.

The @racket[_order] expression must evaluate to either @racket["ASC"] or @racket["DESC"] and the
@racket[_limit] expressions must evaluate to a value suitable for use in the @tt{LIMIT} clause of
@ext-link["https://sqlite.org/lang_select.html"]{a SQLite @tt{SELECT} statement}. An expression that
evaluates to a negative integer (the default) is the same as having no limit.
The @racket[_order] expression must evaluate to either @racket["ASC"] or @racket["DESC"] (or
equivalent symbols) and the @racket[_limit] expressions must evaluate to a value suitable for use in
the @tt{LIMIT} clause of @ext-link["https://sqlite.org/lang_select.html"]{a SQLite @tt{SELECT}
statement}. An expression that evaluates to a negative integer (the default) is the same as having
no limit.

Typically you will pass these functions by name to listing functions like @racket[fenced-listing]
rather than calling them directly.

@examples[#:eval example-eval
(articles 'full)]
}

                           [published            string/f]
                           [updated              string/f]
                           [author               string/f]
                           [conceal              string/f]
                           [series-page          string/f]
                           [noun-singular        string/f]
                           [note-count           integer/f]
                           [doc-html             string/f]
                           [content-html         string/f]
                           [disposition          string/f]
                           [disp-html-anchor     string/f]
                           [listing-full-html    string/f]
                           [listing-excerpt-html string/f]
                           [listing-short-html   string/f])
            #:constructor-name make-cache:article]{

                               [html-anchor string/f])
                              #:constructor-name make-cache:index-entry]{
                              
Table holding cached information about index entries found in articles.

}

@defstruct*[listing ([html        string/f]
                     [published   date/f]
                     [series-page symbol/f])
@defstruct*[listing ([path        string/f]
                     [title       string/f]
                     [author      string/f]
                     [published   string/f]
                     [updated     string/f]
                     [html        string/f])
                    #:constructor-name make-listing]{

This is not a table that persists in the cache database; rather it is the schema targeted by
@racket[articles] and @racket[articles+notes] using deta’s @racket[project-onto].
This is a “virtual” schema targeted by @racket[articles] and @racket[articles+notes] using deta’s
@racket[project-onto]. It supplies the minimum set of fields needed to build the RSS feed; most
times (e.g., on @tech{series} pages) only the @tt{html} field is used, via @racket[fenced-listing].

}

                  #:published pubdate
                  #:updated (maybe-meta 'updated)
                  #:author (maybe-meta 'author default-authorname)
                  #:conceal (maybe-meta 'conceal)
                  #:series-page series-node
                  #:noun-singular (maybe-meta 'noun (series-metas-noun))
                  #:note-count (length note-txprs)
                  #:doc-html doc-html
                  #:content-html doc-html
                  #:disposition disposition
                  #:disp-html-anchor disp-note-id
                  #:listing-full-html (string-append header doc-html footer)
                  #:listing-excerpt-html ""
                  #:listing-short-html listing-short))
    (values title-plain (string-append header doc-html notes-section-html footer))))

#lang racket/base

; SPDX-License-Identifier: BlueOak-1.0.0
; This file is licensed under the Blue Oak Model License 1.0.0.

;; Generates an Atom feed from the SQLite cache

(require txexpr
         deta
         racket/match
         racket/file
         racket/date
         racket/string
         db/base
         racket/sequence
         "dust.rkt"
         "cache.rkt")

(provide main)

(define feed-author default-authorname)
(define feed-author-email "joel@jdueck.net")

  (define timestamp
    (parameterize [(date-display-format 'iso-8601)]
      (date->string now #t)))
  (string-append timestamp "Z"))

;; Get the data out of the SQLite cache as vectors
(define (fetch-rows)
  (define fields '(pagenode title_plain published updated author doc_html))
  (define select #<<---
     SELECT `path`, `title`, `published`, `updated`, `author`, `entry_contents` FROM
       (SELECT `page` AS `path`,
               `title_plain` AS `title`,
               `published`,
  (sequence->list
               `updated`,
               `author`,
               `doc_html` AS `entry_contents`
        FROM `articles` WHERE (NOT (`conceal` LIKE "%all%")) AND (NOT (`conceal` LIKE "%feed%"))
        UNION
        SELECT `page` || '#' || `html_anchor` AS `path`,
               `title_plain` AS `title`,
   (in-entities (cache-conn)
               `published`,
               "" AS `updated`,
               `author`,
               `content_html` as `entry_contents`
        FROM `notes` WHERE (NOT (`conceal` LIKE "%all%")) AND (NOT (`conceal` LIKE "%feed%")))
        ORDER BY `published` DESC LIMIT ~a
---
    )
  (query-rows (cache-conn) (format select feed-item-limit)))
                (articles+notes 'content #:series #f #:limit feed-item-limit))))

(define (vector->rss-item vec)
  (match-define
(define (listing->rss-item lst)
  (match-define (listing _ path title author published updated html) lst)
    (vector path title published updated author contents) vec)
  (define entry-url (string-append feed-site-url web-root path))
  (define update-ts
    (cond [(non-empty-string? updated) updated]
  (define updated-ts (if (non-empty-string? updated) updated published))
          [else published]))
    
  `(entry (author    (name ,author))
          (published ,(ymd->rfc3339 published))
          (updated   ,(ymd->rfc3339 update-ts))
          (title     ,title)
  
  `(entry (author (name ,author))
          (published    ,(ymd->rfc3339 published))
          (updated      ,(ymd->rfc3339 updated-ts))
          (title        ,title)
          (link [[rel "alternate"] [href ,entry-url]])
          (id        ,entry-url)
          (id           ,entry-url)
          (summary [[type "html"]]
                   ,(as-cdata contents))))
                   ,(as-cdata html))))

(define (rss-feed)
  (define feed-xpr
    `(feed [[xml:lang "en-us"] [xmlns "http://www.w3.org/2005/Atom"]]
           (title ,feed-title)
           (link [[rel "self"] [href ,(string-append feed-site-url web-root "feed.xml")]])
           (generator [[uri "http://pollenpub.com/"]] "Pollen")
           (id ,(string-append feed-site-url web-root))
           (updated ,(current-rfc3339))
           (author
            (name ,feed-author)
            (email ,@(email-encode feed-author-email)))
           ,@(map vector->rss-item (fetch-rows))))
           ,@(map listing->rss-item (fetch-rows))))
  (string-append "<?xml version=\"1.0\" encoding=\"utf-8\"?>\n"
                 (xexpr->string feed-xpr)))

(define (main)
  (display-to-file (rss-feed) "feed.xml" #:mode 'text #:exists 'replace))