cacheing and mb wrapper

src/sh/api.sh

@@ -1,5 +1,5 @@
 # Argument: MB Artist ID
-mb_browse_releases() {
+__api_mb_browse_releases() {
   $CURL \
     --get \
     --data fmt=json \
@@ -10,7 +10,7 @@ mb_browse_releases() {
 }
 
 # Argument: MB Artist ID
-mb_browse_release_groups() {
+__api_mb_browse_release_groups() {
   $CURL \
     --get \
     --data fmt=json \
@@ -22,7 +22,7 @@ mb_browse_release_groups() {
 }
 
 # Argument: Search string
-mb_search_artists() {
+__api_mb_search_artists() {
   $CURL \
     --get \
     --data fmt=json \
@@ -32,7 +32,7 @@ mb_search_artists() {
 }
 
 # Argument: MB Artist ID
-mb_get_artist() {
+__api_mb_get_artist() {
   $CURL \
     --get \
     --data fmt=json \
@@ -42,7 +42,7 @@ mb_get_artist() {
 }
 
 # Argument: Discogs id
-discogs_get_artist() {
+__api_discogs_get_artist() {
   $CURL \
     --get \
     -A "$APP_NAME/$APP_VERSION ($APP_WEBSITE)" \
@@ -50,7 +50,7 @@ discogs_get_artist() {
 }
 
 # Argument: wikidata id
-wikidata_get_links() {
+__api_wikidata_get_sitelinks() {
   $CURL \
     --get \
     -A "$APP_NAME/$APP_VERSION ($APP_WEBSITE)" \
@@ -58,7 +58,7 @@ wikidata_get_links() {
 }
 
 # Argument: Wikipedia name (last part of URL)
-wikipedia_en_get_summary() {
+__api_wikipedia_en_get_summary() {
   $CURL \
     --get \
     -A "$APP_NAME/$APP_VERSION ($APP_WEBSITE)" \

src/sh/cache.sh

@@ -0,0 +1,72 @@
+CACHEDIR="$HOME/.cache/$APP_NAME"
+[ -d "$CACHEDIR" ] || mkdir "$CACHEDIR"
+
+artist_mb_filename="musicbrainz.json"
+artist_discogs_filename="discogs.json"
+artist_wikidata_filename="wikidata.json"
+artist_enwikipedia_filename="enwikipedia.json"
+
+# Super wrapper
+# argument $1: MusicBrainz Artist ID
+# argument $2: Filename of json file
+__get_artist_json() {
+  f="$CACHEDIR/$1/$2"
+  [ -f "$f" ] || return
+  cat "$f"
+}
+
+# Super wrapper
+# argument $1: MusicBrainz Artist ID
+# argument $2: Filename of json file
+__put_artist_json() {
+  artistdir="$CACHEDIR/$1"
+  [ -d "$artistdir" ] || mkdir "$artistdir"
+  f="$artistdir/$2"
+  tmpf=$(mktemp)
+  cat >"$tmpf"
+  [ -s "$tmpf" ] && mv "$tmpf" "$f" || echo "{}" >"$f"
+}
+
+# Returns the cached MusicBrainz data for the artist given by the MusicBrainz
+# Artist ID in $1
+cache_get_artist_mb() {
+  __get_artist_json "$1" "$artist_mb_filename"
+}
+
+# Returns the cached Discogs data for the artist given by the MusicBrainz
+# Artist ID in $1
+cache_get_artist_discogs() {
+  __get_artist_json "$1" "$artist_discogs_filename"
+}
+
+# Returns the cached Wikipedia (English) data for the artist given by the
+# MusicBrainz Artist ID in $1
+cache_get_artist_enwikipedia() {
+  __get_artist_json "$1" "$artist_enwikipedia_filename"
+}
+
+cache_get_artist_wikidata() {
+  __get_artist_json "$1" "$artist_wikidata_filename"
+}
+
+# Read from stdin the MusicBrainz data for the artist given by the MusicBrainz
+# Artist ID in $1, and cache it.
+cache_put_artist_mb() {
+  cat | __put_artist_json "$1" "$artist_mb_filename"
+}
+
+# Read from stdin the Discogs data for the artist given by the MusicBrainz
+# Artist ID in $1, and cache it.
+cache_put_artist_discogs() {
+  cat | __put_artist_json "$1" "$artist_discogs_filename"
+}
+
+# Read from stdin the Wikipedia data (English) for the artist given by the
+# MusicBrainz Artist ID in $1, and cache it.
+cache_put_artist_enwikipedia() {
+  cat | __put_artist_json "$1" "$artist_enwikipedia_filename"
+}
+
+cache_put_artist_wikidata() {
+  cat | __put_artist_json "$1" "$artist_wikidata_filename"
+}

src/sh/mb.sh

@@ -0,0 +1,56 @@
+# The only IDs uses here are MusicBrainz IDs
+
+__mb_artist_cache_or_fetch() {
+  mbartist="$(cache_get_artist_mb "$1" || true)"
+  if [ ! "$mbartist" ]; then
+    __api_mb_get_artist "$1" | cache_put_artist_mb "$1"
+    mbartist="$(cache_get_artist_mb "$1")"
+  fi
+  echo "$mbartist"
+}
+
+# Get MusicBrainz json for artist
+# @argument $1: MusicBrainz Artist ID
+mb_artist() {
+  __mb_artist_cache_or_fetch "$1"
+}
+
+# Get Wikidata json for artist
+# @argument $1: MusicBrainz Artist ID
+mb_artist_wikidata() {
+  wikidata=$(cache_get_artist_wikidata "$1" || true)
+  if [ ! "$wikidata" ] || [ "$wikidata" = "null" ]; then
+    wikidataid=$(mb_artist "$1" |
+      $JQ -r '.relations |
+      map(select(.type=="wikidata")) |
+      .[0].url.resource' |
+      awk -F "/" '{print $NF}')
+    [ ! "$wikidataid" ] || [ "$wikidataid" != "null" ] || return
+    __api_wikidata_get_sitelinks "$wikidataid" | cache_put_artist_wikidata "$1"
+    wikidata=$(cache_get_artist_wikidata "$1")
+  fi
+  echo "$wikidata"
+}
+
+# Get Wikipedia (English) summary json for artist
+# @argument $1: MusicBrainz Artist ID
+mb_artist_enwikipedia() {
+  enwiki="$(cache_get_artist_enwikipedia "$1" || true)"
+  if [ ! "$enwiki" ] || [ "$enwiki" = "null" ]; then
+    # To fetch the wikipedia data, we need the wikipedia URL
+    # There are two possibly ways to get the wikipedia URL
+    # 1. From the website relations in MB (MB artists donw have wiki rels)
+    # 2. MB website relations -> Wikidata -> Wikipedia
+    # Lately, Wikipedia pages are not stored in the MB artist url relations.
+    # For obvious reasons it is recommended to link to wikidata only. So, we
+    # take the second route.
+    wikidata=$(mb_artist_wikidata "$1" || true)
+    wikiid=$(echo "$wikidata" |
+      $JQ -r '.enwiki.url' |
+      awk -F "/" '{print $NF}')
+    [ ! "$wikiid" ] || [ "$wikiid" != "null" ] || return
+    __api_wikipedia_en_get_summary "$wikiid" | cache_put_artist_enwikipedia "$1"
+    enwiki="$(cache_get_artist_enwikipedia "$1")"
+  fi
+  echo "$enwiki"
+}

src/sh/preview.sh

@@ -1,35 +1,6 @@
-__description_from_wikidata() {
-  wiki=$(wikidata_get_links "$1" | $JQ -r '.enwiki' | awk -F "/" '{print $NF}')
-  [ ! "$wiki" ] || [ "$wiki" = "null" ] && return
-  desc=$(wikipedia_en_get_summary "$wiki" | $JQ -r '.extract')
-  [ ! "$wiki" ] || [ "$wiki" = "null" ] && return
-  echo "$desc"
-}
-
-# For now, this prints the description of the artist.
-#
-# Source of information:
-# 1. Wikipedia
-# 2. Discogs
+# Print preview of artist
+# @input $1: MusicBrainz Artist ID
 __preview_artist() {
-  # Get artist information from MusicBrainz
-  artist_relations=$(mb_get_artist "$1" | $JQ -r ".relations")
-  wikidata=$(echo "$artist_relations" |
-    $JQ -r 'map(select(.type="wikidata")) | .[0].url.resource' |
-    awk -F "/" '{print $NF}')
-  if [ "$wikidata" ] && [ "$wikidata" != "null" ]; then
-    desc=$(__description_from_wikidata "$wikidata")
-  fi
-  # Alternative: Get information from Discogs
-  if [ ! "${desc:-}" ]; then
-    discogs=$(echo "$artist_relations" |
-      $JQ -r 'map(select(.type=="discogs")) | .[0].url.resource' |
-      awk -F "/" '{print $NF}')
-    [ ! "$discogs" ] || [ "$discogs" = "null" ] && return
-    desc=$(discogs_get_artist "$discogs" |
-      $JQ -r '.profile')
-    [ ! "$desc" ] || [ "$desc" = "null" ] && return
-  fi
-
+  desc=$(mb_artist_enwikipedia "$1" | $JQ -r ".extract")
   echo "$desc" | fold -s -w "$FZF_PREVIEW_COLUMNS" | $CAT
 }