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Diffstat (limited to 'app/javascript/flavours/glitch/util/bio_metadata.js')
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diff --git a/app/javascript/flavours/glitch/util/bio_metadata.js b/app/javascript/flavours/glitch/util/bio_metadata.js new file mode 100644 index 000000000..599ec20e2 --- /dev/null +++ b/app/javascript/flavours/glitch/util/bio_metadata.js @@ -0,0 +1,331 @@ +/* + +`util/bio_metadata` +=================== + +> For more information on the contents of this file, please contact: +> +> - kibigo! [@kibi@glitch.social] + +This file provides two functions for dealing with bio metadata. The +functions are: + + - __`processBio(content)` :__ + Processes `content` to extract any frontmatter. The returned + object has two properties: `text`, which contains the text of + `content` sans-frontmatter, and `metadata`, which is an array + of key-value pairs (in two-element array format). If no + frontmatter was provided in `content`, then `metadata` will be + an empty array. + + - __`createBio(note, data)` :__ + Reverses the process in `processBio()`; takes a `note` and an + array of two-element arrays (which should give keys and values) + and outputs a string containing a well-formed bio with + frontmatter. + +*/ + +// * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * + +/*********************************************************************\ + + To my lovely code maintainers, + + The syntax recognized by the Mastodon frontend for its bio metadata + feature is a subset of that provided by the YAML 1.2 specification. + In particular, Mastodon recognizes metadata which is provided as an + implicit YAML map, where each key-value pair takes up only a single + line (no multi-line values are permitted). To simplify the level of + processing required, Mastodon metadata frontmatter has been limited + to only allow those characters in the `c-printable` set, as defined + by the YAML 1.2 specification, instead of permitting those from the + `nb-json` characters inside double-quoted strings like YAML proper. + ¶ It is important to note that Mastodon only borrows the *syntax* + of YAML, not its semantics. This is to say, Mastodon won't make any + attempt to interpret the data it receives. `true` will not become a + boolean; `56` will not be interpreted as a number. Rather, each key + and every value will be read as a string, and as a string they will + remain. The order of the pairs is unchanged, and any duplicate keys + are preserved. However, YAML escape sequences will be replaced with + the proper interpretations according to the YAML 1.2 specification. + ¶ The implementation provided below interprets `<br>` as `\n` and + allows for an open <p> tag at the beginning of the bio. It replaces + the escaped character entities `'` and `"` with single or + double quotes, respectively, prior to processing. However, no other + escaped characters are replaced, not even those which might have an + impact on the syntax otherwise. These minor allowances are provided + because the Mastodon backend will insert these things automatically + into a bio before sending it through the API, so it is important we + account for them. Aside from this, the YAML frontmatter must be the + very first thing in the bio, leading with three consecutive hyphen- + minues (`---`), and ending with the same or, alternatively, instead + with three periods (`...`). No limits have been set with respect to + the number of characters permitted in the frontmatter, although one + should note that only limited space is provided for them in the UI. + ¶ The regular expression used to check the existence of, and then + process, the YAML frontmatter has been split into a number of small + components in the code below, in the vain hope that it will be much + easier to read and to maintain. I leave it to the future readers of + this code to determine the extent of my successes in this endeavor. + + UPDATE 19 Oct 2017: We no longer allow character escapes inside our + double-quoted strings for ease of processing. We now internally use + the name "ƔAML" in our code to clarify that this is Not Quite YAML. + + Sending love + warmth eternal, + - kibigo [@kibi@glitch.social] + +\*********************************************************************/ + +/* "u" FLAG COMPATABILITY */ + +let compat_mode = false; +try { + new RegExp('.', 'u'); +} catch (e) { + compat_mode = true; +} + +/* CONVENIENCE FUNCTIONS */ + +const unirex = str => compat_mode ? new RegExp(str) : new RegExp(str, 'u'); +const rexstr = exp => '(?:' + exp.source + ')'; + +/* CHARACTER CLASSES */ + +const DOCUMENT_START = /^/; +const DOCUMENT_END = /$/; +const ALLOWED_CHAR = unirex( // `c-printable` in the YAML 1.2 spec. + compat_mode ? '[\t\n\r\x20-\x7e\x85\xa0-\ufffd]' : '[\t\n\r\x20-\x7e\x85\xa0-\ud7ff\ue000-\ufffd\u{10000}-\u{10FFFF}]' + ); +const WHITE_SPACE = /[ \t]/; +const LINE_BREAK = /\r?\n|\r|<br\s*\/?>/; +const INDICATOR = /[-?:,[\]{}&#*!|>'"%@`]/; +const FLOW_CHAR = /[,[\]{}]/; + +/* NEGATED CHARACTER CLASSES */ + +const NOT_WHITE_SPACE = unirex('(?!' + rexstr(WHITE_SPACE) + ')[^]'); +const NOT_LINE_BREAK = unirex('(?!' + rexstr(LINE_BREAK) + ')[^]'); +const NOT_INDICATOR = unirex('(?!' + rexstr(INDICATOR) + ')[^]'); +const NOT_FLOW_CHAR = unirex('(?!' + rexstr(FLOW_CHAR) + ')[^]'); +const NOT_ALLOWED_CHAR = unirex( + '(?!' + rexstr(ALLOWED_CHAR) + ')[^]' +); + +/* BASIC CONSTRUCTS */ + +const ANY_WHITE_SPACE = unirex(rexstr(WHITE_SPACE) + '*'); +const ANY_ALLOWED_CHARS = unirex(rexstr(ALLOWED_CHAR) + '*'); +const NEW_LINE = unirex( + rexstr(ANY_WHITE_SPACE) + rexstr(LINE_BREAK) +); +const SOME_NEW_LINES = unirex( + '(?:' + rexstr(NEW_LINE) + ')+' +); +const POSSIBLE_STARTS = unirex( + rexstr(DOCUMENT_START) + rexstr(/<p[^<>]*>/) + '?' +); +const POSSIBLE_ENDS = unirex( + rexstr(SOME_NEW_LINES) + '|' + + rexstr(DOCUMENT_END) + '|' + + rexstr(/<\/p>/) +); +const QUOTE_CHAR = unirex( + '(?=' + rexstr(NOT_LINE_BREAK) + ')[^"]' +); +const ANY_QUOTE_CHAR = unirex( + rexstr(QUOTE_CHAR) + '*' +); + +const ESCAPED_APOS = unirex( + '(?=' + rexstr(NOT_LINE_BREAK) + ')' + rexstr(/[^']|''/) +); +const ANY_ESCAPED_APOS = unirex( + rexstr(ESCAPED_APOS) + '*' +); +const FIRST_KEY_CHAR = unirex( + '(?=' + rexstr(NOT_LINE_BREAK) + ')' + + '(?=' + rexstr(NOT_WHITE_SPACE) + ')' + + rexstr(NOT_INDICATOR) + '|' + + rexstr(/[?:-]/) + + '(?=' + rexstr(NOT_LINE_BREAK) + ')' + + '(?=' + rexstr(NOT_WHITE_SPACE) + ')' + + '(?=' + rexstr(NOT_FLOW_CHAR) + ')' +); +const FIRST_VALUE_CHAR = unirex( + '(?=' + rexstr(NOT_LINE_BREAK) + ')' + + '(?=' + rexstr(NOT_WHITE_SPACE) + ')' + + rexstr(NOT_INDICATOR) + '|' + + rexstr(/[?:-]/) + + '(?=' + rexstr(NOT_LINE_BREAK) + ')' + + '(?=' + rexstr(NOT_WHITE_SPACE) + ')' + // Flow indicators are allowed in values. +); +const LATER_KEY_CHAR = unirex( + rexstr(WHITE_SPACE) + '|' + + '(?=' + rexstr(NOT_LINE_BREAK) + ')' + + '(?=' + rexstr(NOT_WHITE_SPACE) + ')' + + '(?=' + rexstr(NOT_FLOW_CHAR) + ')' + + rexstr(/[^:#]#?/) + '|' + + rexstr(/:/) + '(?=' + rexstr(NOT_WHITE_SPACE) + ')' +); +const LATER_VALUE_CHAR = unirex( + rexstr(WHITE_SPACE) + '|' + + '(?=' + rexstr(NOT_LINE_BREAK) + ')' + + '(?=' + rexstr(NOT_WHITE_SPACE) + ')' + + // Flow indicators are allowed in values. + rexstr(/[^:#]#?/) + '|' + + rexstr(/:/) + '(?=' + rexstr(NOT_WHITE_SPACE) + ')' +); + +/* YAML CONSTRUCTS */ + +const ƔAML_START = unirex( + rexstr(ANY_WHITE_SPACE) + '---' +); +const ƔAML_END = unirex( + rexstr(ANY_WHITE_SPACE) + '(?:---|\.\.\.)' +); +const ƔAML_LOOKAHEAD = unirex( + '(?=' + + rexstr(ƔAML_START) + + rexstr(ANY_ALLOWED_CHARS) + rexstr(NEW_LINE) + + rexstr(ƔAML_END) + rexstr(POSSIBLE_ENDS) + + ')' +); +const ƔAML_DOUBLE_QUOTE = unirex( + '"' + rexstr(ANY_QUOTE_CHAR) + '"' +); +const ƔAML_SINGLE_QUOTE = unirex( + '\'' + rexstr(ANY_ESCAPED_APOS) + '\'' +); +const ƔAML_SIMPLE_KEY = unirex( + rexstr(FIRST_KEY_CHAR) + rexstr(LATER_KEY_CHAR) + '*' +); +const ƔAML_SIMPLE_VALUE = unirex( + rexstr(FIRST_VALUE_CHAR) + rexstr(LATER_VALUE_CHAR) + '*' +); +const ƔAML_KEY = unirex( + rexstr(ƔAML_DOUBLE_QUOTE) + '|' + + rexstr(ƔAML_SINGLE_QUOTE) + '|' + + rexstr(ƔAML_SIMPLE_KEY) +); +const ƔAML_VALUE = unirex( + rexstr(ƔAML_DOUBLE_QUOTE) + '|' + + rexstr(ƔAML_SINGLE_QUOTE) + '|' + + rexstr(ƔAML_SIMPLE_VALUE) +); +const ƔAML_SEPARATOR = unirex( + rexstr(ANY_WHITE_SPACE) + + ':' + rexstr(WHITE_SPACE) + + rexstr(ANY_WHITE_SPACE) +); +const ƔAML_LINE = unirex( + '(' + rexstr(ƔAML_KEY) + ')' + + rexstr(ƔAML_SEPARATOR) + + '(' + rexstr(ƔAML_VALUE) + ')' +); + +/* FRONTMATTER REGEX */ + +const ƔAML_FRONTMATTER = unirex( + rexstr(POSSIBLE_STARTS) + + rexstr(ƔAML_LOOKAHEAD) + + rexstr(ƔAML_START) + rexstr(SOME_NEW_LINES) + + '(?:' + + rexstr(ANY_WHITE_SPACE) + rexstr(ƔAML_LINE) + rexstr(SOME_NEW_LINES) + + '){0,5}' + + rexstr(ƔAML_END) + rexstr(POSSIBLE_ENDS) +); + +/* SEARCHES */ + +const FIND_ƔAML_LINE = unirex( + rexstr(NEW_LINE) + rexstr(ANY_WHITE_SPACE) + rexstr(ƔAML_LINE) +); + +/* STRING PROCESSING */ + +function processString (str) { + switch (str.charAt(0)) { + case '"': + return str.substring(1, str.length - 1); + case '\'': + return str + .substring(1, str.length - 1) + .replace(/''/g, '\''); + default: + return str; + } +} + +/* BIO PROCESSING */ + +export function processBio(content) { + content = content.replace(/"/g, '"').replace(/'/g, '\''); + let result = { + text: content, + metadata: [], + }; + let ɣaml = content.match(ƔAML_FRONTMATTER); + if (!ɣaml) { + return result; + } else { + ɣaml = ɣaml[0]; + } + const start = content.search(ƔAML_START); + const end = start + ɣaml.length - ɣaml.search(ƔAML_START); + result.text = content.substr(end); + let metadata = null; + let query = new RegExp(rexstr(FIND_ƔAML_LINE), 'g'); // Some browsers don't allow flags unless both args are strings + while ((metadata = query.exec(ɣaml))) { + result.metadata.push([ + processString(metadata[1]), + processString(metadata[2]), + ]); + } + return result; +} + +/* BIO CREATION */ + +export function createBio(note, data) { + if (!note) note = ''; + let frontmatter = ''; + if ((data && data.length) || note.match(/^\s*---\s+/)) { + if (!data) frontmatter = '---\n...\n'; + else { + frontmatter += '---\n'; + for (let i = 0; i < data.length; i++) { + let key = '' + data[i][0]; + let val = '' + data[i][1]; + + // Key processing + if (key === (key.match(ƔAML_SIMPLE_KEY) || [])[0]) /* do nothing */; + else if (key === (key.match(ANY_QUOTE_CHAR) || [])[0]) key = '"' + key + '"'; + else { + key = key + .replace(/'/g, '\'\'') + .replace(new RegExp(rexstr(NOT_ALLOWED_CHAR), compat_mode ? 'g' : 'gu'), '�'); + key = '\'' + key + '\''; + } + + // Value processing + if (val === (val.match(ƔAML_SIMPLE_VALUE) || [])[0]) /* do nothing */; + else if (val === (val.match(ANY_QUOTE_CHAR) || [])[0]) val = '"' + val + '"'; + else { + key = key + .replace(/'/g, '\'\'') + .replace(new RegExp(rexstr(NOT_ALLOWED_CHAR), compat_mode ? 'g' : 'gu'), '�'); + key = '\'' + key + '\''; + } + + frontmatter += key + ': ' + val + '\n'; + } + frontmatter += '...\n'; + } + } + return frontmatter + note; +} |