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# Each completer implements three functions:
#
# match: can this completer be used for this search URL?
# getUrl: map these query terms to a completion URL.
# parse: extract suggestions from the resulting (successful) XMLHttpRequest.
#
Google =
name: "Google"
match: (searchUrl) ->
true # TBD.
getUrl: (queryTerms) ->
"http://suggestqueries.google.com/complete/search?ss_protocol=legace&client=toolbar&q=#{Utils.createSearchQuery queryTerms}"
parse: (xhr, callback) ->
if suggestions = xhr?.responseXML?.getElementsByTagName "suggestion"
suggestions =
for suggestion in suggestions
continue unless suggestion = suggestion.getAttribute "data"
suggestion
callback suggestions
else
callback []
# A dummy search engine which is guaranteed to match any search URL, but produces no completions. This allows
# the rest of the logic to be written knowing that there will be a search engine match.
DummySearchEngine =
name: "Dummy"
match: -> true
# We return a useless URL which we know will succeed, but which won't generate any network traffic.
getUrl: -> chrome.runtime.getURL "content_scripts/vimium.css"
parse: (_, callback) -> callback []
CompletionEngines = [ Google, DummySearchEngine ]
SearchEngines =
cancel: (searchUrl, callback = null) ->
@requests[searchUrl]?.abort()
delete @requests[searchUrl]
callback? null
# Perform and HTTP GET.
# searchUrl is the search engine's URL, e.g. Settings.get("searchUrl")
# url is the URL to fetch
# callback will be called a successful XMLHttpRequest object, or null.
get: (searchUrl, url, callback) ->
@requests ?= {} # Maps searchUrls to any outstanding HTTP request for that search engine.
@cancel searchUrl
# We cache the results of recent requests (with a two-hour expiry).
@requestCache ?= new SimpleCache 2 * 60 * 60 * 1000
if @requestCache.has url
callback @requestCache.get url
return
@requests[searchUrl] = xhr = new XMLHttpRequest()
xhr.open "GET", url, true
xhr.timeout = 500
xhr.ontimeout = => @cancel searchUrl, callback
xhr.onerror = => @cancel searchUrl, callback
xhr.send()
xhr.onreadystatechange = =>
if xhr.readyState == 4
if xhr.status == 200
@requests[searchUrl] = null
callback @requestCache.set url, xhr
else
callback null
# Look up the search engine for this search URL. Because of DummySearchEngine, above, we know there will
# always be a match. Imagining that there may be many search engines, and knowing that this is called for
# every character entered, we cache the result.
lookupEngine: (searchUrl) ->
@engineCache ?= new SimpleCache 24 * 60 * 60 * 1000
if @engineCache.has searchUrl
@engineCache.get searchUrl
else
for engine in CompletionEngines
return @engineCache.set searchUrl, engine if engine.match searchUrl
# This is the main (actually, the only) entry point.
# searchUrl is the search engine's URL, e.g. Settings.get("searchUrl")
# queryTerms are the queryTerms
# callback will be applied to a list of suggestion strings (which will be an empty list, if anything goes
# wrong).
complete: (searchUrl, queryTerms, callback) ->
return callback [] unless 0 < queryTerms.length
# Don't try to complete general URLs.
return callback [] if 1 == queryTerms.length and Utils.isUrl queryTerms[0]
# Don't try to complete Javascrip URLs.
return callback [] if 0 < queryTerms.length and Utils.hasJavascriptPrefix queryTerms[0]
engine = @lookupEngine searchUrl
url = engine.getUrl queryTerms
@get searchUrl, url, (xhr = null) ->
if xhr? then engine.parse xhr, callback else callback []
root = exports ? window
root.SearchEngines = SearchEngines
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