[342] This specification defines a set of steps that can be used to
parse feeds in the wild.
[346] This specification supports feed using following formats and modules:
[15] A feed has
entries entries , and
authors persons .
They are initially empty.
[39] A feed has
page URL feed URL previous feed URL next feed URL icon logo updated null .
[226] A feed has
title subtitle description null . They can be null , a string , or a Node
[28] An entry has
authors persons ,
categories enclosures enclosures .
They are initially empty.
[88] An entry has
feed page URL thumbnail duration published updated null .
[227] An entry has
title summary content null . They can be null , a string , or a Node
[81] To get the computed authors entry entry , run these steps:[82] If entry 's authors entry 's authors [83] Otherwise, if entry 's feed entry 's feed authors [84] Otherwise, return an empty list.
[93] To get the computed updated entry entry , run these steps:[94] If entry 's updated null ,
return entry 's updated [97] Otherwise, if entry 's published null ,
return entry 's published [95] Otherwise, if entry 's feed entry 's feed updated [96] Otherwise, returnthe current timestamp.
[29] A person is a tuple of
name email page URL icon null .
[160] An image has
URL width height null .
[188] An enclosure has
URL MIME type length null .
[344] An implementation that supports this specification MUST process a feed response to parse a response as a feed.
[345] An implementation that supports this specification MUST process a feed document to parse a Document
[372] To process a URL element element , run these steps:[35] Let text be element 's child text content [196] If text is the empty string , return null and abort these steps.[36] Parse text relative to element 's node document [38] If not failed, return the resulting URL string .[373] Otherwise, return null .
[130] The link relation link Atom namespace or in the Atom 0.3 namespace
element is the value returned by the following steps:[131] If element does not have a rel [132] Return http://www.iana.org/assignments/relation/alternate [134] Otherwise:[135] Let rel be element 's rel [136] If rel contains a : [137] Return rel .[138] Otherwise:[133] Return http://www.iana.org/assignments/relation/ rel .
[140] The href URL link Atom namespace or in the Atom 0.3 namespace
element is the value returned by the following steps:[141] Let text be element 's href [142] Parse text relative to element 's node document [143] If failed, return null .[144] Otherwise, return the resulting URL record .
[234] To process an Atom link element for object
with type , run these steps:
[139] If element 's link relation http://www.iana.org/assignments/relation/alternate [145] If object 's page URL null :[146] Set object 's page URL child 's href URL [235] If mode is feed [150] If element 's link relation http://www.iana.org/assignments/relation/self [151] If object 's feed URL null :[152] Set object 's feed URL child 's href URL [199] If element 's link relation http://www.iana.org/assignments/relation/prev http://www.iana.org/assignments/relation/previous [201] If object 's previous feed URL null :[202] Set object 's previous feed URL child 's href URL [203] If element 's link relation http://www.iana.org/assignments/relation/next [204] If object 's next feed URL null :[205] Set object 's next feed URL child 's href URL [269] If mode is entry [270] If element 's link relation http://www.iana.org/assignments/relation/enclosure [336] Let url be child 's href URL [337] If url is not null :[271] Let enclosure be an enclosure ,
whose URL url .[273] Set enclosure 's type child 's
type [275] Let length be child 's length [276] If length is not null:[277] Let n be the result of applying the
rules for parsing non-negative integers to length .[278] If n is not an error and n is greater than zero:[274] Set enclosure 's length n .[272] Append enclosure to object 's enclosures [176] To process an image element element with string
attribute name , run these steps:
[161] Let text be element 's attribute name attribute value.[170] If text is not null or the empty string :[179] Parse text relative to element 's node document [187] If not failed:[228] Let image be an image .[229] Set image 's URL resulting URL string .[297] Let w be the result of applying the
rules for parsing non-negative integers to element 's width [298] If w is not an error, set image 's width w .[299] Let h be the result of applying the
rules for parsing non-negative integers to element 's height [300] If h is not an error, set image 's height h .[296] Return image and abort these steps.[177] Return null .[24] To process an Atom person element , run these steps:[54] Let person be a person .[55] For each element child in element 's children [56] Switch by child 's namespace local name name Atom namespace or in the Atom 0.3 namespace
If person 's name null ,
set person 's name processing a string element child . email Atom namespace or in the Atom 0.3 namespace
If person 's email null ,
set person 's email processing a string element child . uri Atom namespace or in the Atom 0.3 namespace
If person 's page URL null ,
set person 's page URL processing a URL element child . image GData namespace
If person 's icon null ,
set person 's icon processing an image element child
with attribute name src [53] Return person .
[247] To process an RSS 2.0 person element , run these steps:[254] Let person be a person .[253] Let text be element 's child text content [318] If text is the empty string :[319] Return null .[157] Otherwise, if text is
one or more Unicode code points that are not space characters ,
followed by one or more space characters ,
followed by a ( Unicode code points ,
followed by a ) [158] Set person 's name ( ) text , not inclusive.[159] Set person 's email space character in text .[320] Otherwise:[255] Set person 's name text .[256] Return person .
[60] To process a string element element , run these steps:[98] Let text be element 's child text content [99] If text contains a Unicode code point that is not a space character :[100] Return text .[164] Otherwise:[174] Return null .
[50] To process an Atom text element , run these steps:[61] Let type be the type element , if any, or null .[62] If type is html [267] Return the result of parsing escaped HTML content of element .[63] Otherwise, if type is xhtml element 's children div [66] Let div be a clone of element 's
first div clone children flag set.[67] Let fragment be a DocumentFragment node document element 's node document [68] For each child node in div 's children insert node into fragment .[104] Sanitize fragment .[105] If fragment has significant content :[69] Return fragment .[106] Otherwise:[107] Return null .[64] Otherwise:[65] Let text be element 's child text content [45] If text contains a Unicode code point that is not a space character :[46] Return text .[47] Otherwise:[48] Return null .
[153] To process an Atom 0.3 content element , run these steps:[155] Let mode be element 's mode xml [154] Let type be element 's type text/plain [175] Let text be element 's child text content [162] If mode is escaped [180] If type is equal to text/html ASCII case-insensitive ):[268] Return the result of parsing escaped HTML content of element and abort these steps.[49] If text contains a Unicode code point that is not a space character :[57] Return text .[58] Otherwise:[59] Return null .
[178] To parse escaped HTML content of element element , run these steps:[101] Let text be element 's child text content [73] Let div be a div node document element 's node document [74] Let fragment be a DocumentFragment node document element 's node document [70] Let nodes be the result of running the HTML fragment parsing algorithm
with context set to div and input set to text .[71] For each item node in nodes , in order,
insert node into fragment .[108] Sanitize fragment .[109] If fragment has significant content :[339] If fragment 's children Text [340] Return fragment 's children data [341] Otherwise:[72] Return fragment .[110] Otherwise:[111] Return null .
[112] To sanitize Node node , run these steps:[113] If there is
an img width 1 height 1 remove it from its parent
[114] A Node node has significant content if
there is a feed significant content inclusive descendant of node ,
which is not an inclusive descendant of
an element matching one of the following conditions
which is an inclusive descendant of node :
[129] A Node feed significant content if
it is a palpable content and is an embedded content .
[362] Two inputs A and B are same text content
iff :both A and B are string s and they are equal, or both A and B are Node equal .
[262] To cleanup entry entry , run these steps:[263] If entry 's page URL null and
there is an enclosure whose URL entry 's page URL entry 's enclosures [264] Set entry 's page URL null .[332] If entry 's page URL null ,
entry 's thumbnail null ,
and there is an enclosure whose
type image/ ASCII case-insensitive ) or
whose type null and
URL .jpeg .jpg .png [334] Let enclosure be the first such enclosure .[333] Let image be an image whose URL enclosure 's URL [335] Remove enclosure from entry 's enclosures [265] If
entry 's title entry 's subtitle same text content ,
set entry 's subtitle null .[266] If
entry 's title entry 's summary same text content ,
set entry 's summary null .[291] If
entry 's summary entry 's content same text content ,
set entry 's content null .
[52] To process an Atom entry element , run these steps:[78] Let entry be an entry .[79] For each element child in element 's children [80] Switch by child 's namespace local name author Atom namespace or in the Atom 0.3 namespace
Append the result of processing an Atom person child
to entry 's authors category Atom namespace [30] If child has a term [44] Let term be child 's term [89] If term is not an empty string,
add term to entry 's categories subject Dublin Core namespace [90] Let term be child 's child text content [91] If term is not an empty string,
add term to entry 's categories published Atom namespace
If entry 's published null ,
set entry 's published processing an Atom date child . created Atom 0.3 namespace or in the Atom namespace
If entry 's published null ,
set entry 's published processing a W3C-DTF date child . updated Atom namespace
If entry 's updated null ,
set entry 's updated processing an Atom date child . modified Atom 0.3 namespace or in the Atom namespace
If entry 's updated null ,
set entry 's updated processing a W3C-DTF date child . title Atom namespace
If entry 's title null ,
set entry 's title processing an Atom text child . title Atom 0.3 namespace
If entry 's title null ,
set entry 's title processing an Atom 0.3 content child . summary Atom namespace
If entry 's summary null ,
set entry 's summary processing an Atom text child . summary Atom 0.3 namespace
If entry 's summary null ,
set entry 's summary processing an Atom 0.3 content child . content Atom namespace
If entry 's content null ,
set entry 's content processing an Atom text child . content Atom 0.3 namespace
If entry 's content null ,
set entry 's content processing an Atom 0.3 content child . link Atom namespace or in the Atom 0.3 namespace
Process an Atom link child for entry , with type entry thumbnail Media RSS namespace
If entry 's thumbnail null ,
set entry 's thumbnail processing an image element child
with attribute name url group Media RSS namespace [116] For each element gc in child 's children [117] Switch by gc 's namespace local name title Media RSS namespace
If entry 's title null ,
set entry 's title processing a string element gc . description Media RSS namespace
If entry 's summary null ,
set entry 's summary processing a string element gc . thumbnail Media RSS namespace
If entry 's thumbnail null ,
set entry 's thumbnail processing an image element child
with attribute name url content Media RSS namespace [123] Let enclosure be an enclosure .[124] Let text be gc 's url [125] If text is not null or the empty string :[126] Parse text relative to gc 's node document [127] If not failed:[163] Set enclosure 's URL resulting URL string .[165] Set enclosure 's type gc 's
type [171] Append enclosure to object 's enclosures [246] Return entry .
RSS 2.0 and RSS 0.9x items [249] To process an RSS 2.0 item element , run these steps:[248] Let entry be an entry .[250] For each element child in element 's children [251] Switch by child 's namespace local name category null namespace [92] Let term be child 's child text content [293] If term is not the empty string,
add term to entry 's categories author null namespace [355] Let person be the result of processing an RSS 2.0 person child .[361] If person is not null :[356] If person 's email null ,
or if there is no person whose name person 's name entry 's authors [354] Append person to entry 's authors creator Dublin Core namespace or author iTunes namespace [118] Let text be element 's child text content [119] If text is not the empty string and
there is no person whose name text
in entry 's authors [120] Append a person whose name text
to entry 's authors pubDate null namespace
If entry 's published null ,
set entry 's published processing an RSS 2.0 date child . updated Atom namespace
If entry 's updated null ,
set entry 's updated processing an Atom date child . link null namespace
If entry 's page URL null ,
set entry 's page URL processing a URL element child . thumbnail Media RSS namespace
If entry 's thumbnail null ,
set entry 's thumbnail processing an image element child
with attribute name url image iTunes namespace
If entry 's thumbnail null ,
set entry 's thumbnail processing an image element child
with attribute name href content Media RSS namespace [292] Let enclosure be an enclosure .[364] Let text be child 's url [366] If text is not null or the empty string :[367] Parse text relative to child 's node document [368] If not failed:[369] Set enclosure 's URL resulting URL string .[370] Set enclosure 's type child 's
type [371] Append enclosure to object 's enclosures enclosure null namespace [279] Let enclosure be an enclosure .[280] Let text be child 's url [281] If text is not null or the empty string :[282] Parse text relative to child 's node document [283] If not failed:[195] Set enclosure 's URL resulting URL string .[284] Set enclosure 's type child 's
type [285] Let length be child 's length [286] If length is not null:[287] Let n be the result of applying the
rules for parsing non-negative integers to length .[288] If n is not an error and n is greater than zero:[289] Set enclosure 's length n .[290] Append enclosure to object 's enclosures title null namespace
If entry 's title null ,
set entry 's title processing a string element child . subtitle iTunes namespace
If entry 's subtitle null ,
set entry 's subtitle processing a string element child . description null namespace
If entry 's summary null ,
set entry 's summary parsing escaped HTML content of child . summary iTunes namespace
If entry 's subtitle null ,
set entry 's subtitle processing a string element child . encoded RSS content namespace
If entry 's content null ,
set entry 's content parsing escaped HTML content of child . duration iTunes namespace [218] If entry 's duration null :[198] Let text be child 's child text content [212] If text is one or more ASCII digits :[217] Set entry 's duration ASCII digits in text , interpreted as a decimal number.[215] Otherwise, if text is one or more ASCII digits ,
followed by a : ASCII digits :[223] Set m to the first sequence of ASCII digits in text ,
interpreted as a decimal number.[224] Set s to the second sequence of ASCII digits in text ,
interpreted as a decimal number.[230] Set entry 's duration m × 60 + s [216] Otherwise, if text is one or more ASCII digits ,
followed by a : ASCII digits ,
followed by a : ASCII digits :[231] Set h to the first sequence of ASCII digits in text ,
interpreted as a decimal number.[232] Set m to the second sequence of ASCII digits in text ,
interpreted as a decimal number.[233] Set s to the third sequence of ASCII digits in text ,
interpreted as a decimal number.[257] Set entry 's duration h × 3600 + m × 60 + s [252] Return entry .
[1] To process a feed response res , run these steps:[9] If res is a network error or
res 's status 200 null and abort these steps.[2] Let type be res 's computed MIME type [3] If type is an XML MIME type :[7] Let doc be a Document [6] Let parser be an XML parser associated with doc .
The XML parser MUST XML5 .
It MUST NOT fetch and process external entities .[8] Run parser , using res 's body input byte stream charset Content-Type header value of res , if any, is used as
the encoding label provided by the underlying transport.[11] Set doc 's address res 's url [27] Set doc 's character encoding character encoding used by parser .[5] Return the result of processing a feed document doc .[4] Otherwise, return null .
[10] To process a feed document doc , run these steps:[12] Let root be doc 's root element [17] Switch by root :[16] If it is a feed Atom namespace or in the Atom 0.3 namespace
Let feed be the result of processing an Atom feed element root . [19] If it is an rss null namespace
Let feed be the result of processing an rss element root . [18] If it is an RDF RDF namespace
Let feed be the result of processing an RDF element root . [350] If feed is not null , cleanup feed feed .[13] Return feed .
[351] To cleanup feed feed , run these steps:[352] If feed 's logo null ,
feed 's icon null , and
feed 's logo URL feed 's icon URL [353] Set feed 's icon null .
[20] To process an Atom feed element element , run these steps:[14] Let feed be a feed .[21] For each element child in element 's children [22] Switch by child 's namespace local name title Atom namespace
If feed 's title null ,
set feed 's title processing an Atom text child . title Atom 0.3 namespace
If feed 's title null ,
set feed 's title processing an Atom 0.3 content child . subtitle Atom namespace
If feed 's subtitle null ,
set feed 's subtitle processing an Atom text child . tagline Atom 0.3 namespace
If feed 's subtitle null ,
set feed 's subtitle processing an Atom 0.3 content child . updated Atom namespace
If feed 's updated null ,
set feed 's updated processing an Atom date child . modified Atom 0.3 namespace or in the Atom namespace
If feed 's updated null ,
set feed 's updated processing a W3C-DTF date child . link Atom namespace or in the Atom 0.3 namespace
Process an Atom link child for feed , with type feed icon Atom namespace [181] If feed 's icon null :[184] Let image be an image .[183] Set image 's URL processing a URL element child .[182] If image 's URL null ,
set feed 's icon image .logo Atom namespace [185] If feed 's logo URL null :[186] Let image be an image .[197] Set image 's URL processing a URL element child .[225] If image 's URL null ,
set feed 's logo image .author Atom namespace or in the Atom 0.3 namespace
Append the result of processing an Atom person child
to feed 's authors entry Atom namespace or in the Atom 0.3 namespace [86] Let entry be the result of processing an Atom entry
child .[85] Set entry 's feed feed .[258] Cleanup entry entry .[87] Append entry to feed 's entries [25] Return feed .
RSS 2.0 and RSS 0.9x feeds [301] To process an rss element element , run these steps:[239] Let feed be a feed .[240] For each element child in element 's children [302] Switch by child 's namespace local name channel null namespace
Process an RSS 2.0 channel element with feed . item null namespace [242] Let entry be the result of processing an RSS 2.0 item
child .[243] Set entry 's feed feed .[259] Cleanup entry entry .[244] Append entry to feed 's entries [245] Return feed .
[206] To process an RSS 2.0 channel element with feed feed ,
run these steps:[208] For each element child in element 's children [209] Switch by child 's namespace local name image null namespace [211] If feed 's logo null :[213] Let element be child 's first url null namespace .[214] If element is not null :[308] Let url be the result of
processing a URL element element .[37] If url is not null :[310] Let image be an image .[314] Set image 's URL url .[309] Set feed 's logo image .image iTunes namespace
If feed 's icon null ,
set feed 's icon processing an image element child
with attribute name href creator Dublin Core namespace or author iTunes namespace [316] Let text be element 's child text content [317] If text is not the empty string and
there is no person whose name text
in feed 's authors [315] Append a person whose name text
to feed 's authors managingEditor null namespace [357] Let person be the result of processing an RSS 2.0 person child .[360] If person is not null :[358] If person 's email null ,
or if there is no person whose name person 's name feed 's authors [359] Append person to feed 's authors pubDate lastBuildDate null namespace
If feed 's updated null ,
set feed 's updated processing an RSS 2.0 date child . title null namespace
If feed 's title null ,
set feed 's title processing a string element child . subtitle iTunes namespace
If feed 's subtitle null ,
set feed 's subtitle processing a string element child . description null namespace or summary iTunes namespace
If feed 's description null ,
set feed 's description processing a string element child . link null namespace
If feed 's page URL null ,
set feed 's page URL processing a URL element child . link Atom namespace
Process an Atom link child for feed , with type feed item null namespace [147] Let entry be the result of processing an RSS 2.0 item
child .[148] Set entry 's feed feed .[261] Cleanup entry entry .[149] Append entry to feed 's entries
[43] The key word MUST RFC 2119 .
[34] The terms ASCII digits URL record URL Standard .
[42] The terms MIME type computed MIME type type parse a MIME type MIME Sniffing Standard .
[41] The terms response status url network error Fetch Standard .
[26] The interfaces Node DocumentFragment DOM Standard .
[31] The terms parent children inclusive descendant insert remove clone equals Node local name namespace node document DOM Standard .
[23] The terms
XML MIME type Unicode code point space characters ASCII case-insensitive parse a URL resulting URL string resulting URL string rules for parsing non-negative integers document's address document's character encoding palpable content embedded content child text content input byte stream HTML fragment parsing algorithm HTML parser XML parser HTML Standard .
[32] The div img HTML Standard .
