- Author:
- David Nickerson <nickerso@users.sourceforge.net>
- Date:
- 2009-07-16 02:00:03+12:00
- Desc:
- the starting point for the HH tutorial example
- Permanent Source URI:
- https://models.fieldml.org/workspace/a1/rawfile/f6a8f90307388eb4b040ee3566b84d88b59247f7/dojo-presentation/js/dojo/dojox/data/FlickrRestStore.js
dojo.provide("dojox.data.FlickrRestStore");
dojo.require("dojox.data.FlickrStore");
dojo.declare("dojox.data.FlickrRestStore",
dojox.data.FlickrStore, {
constructor: function(/*Object*/args){
// summary:
// Initializer for the FlickrRestStore store.
// description:
// The FlickrRestStore is a Datastore interface to one of the basic services
// of the Flickr service, the public photo feed. This does not provide
// access to all the services of Flickr.
// This store cannot do * and ? filtering as the flickr service
// provides no interface for wildcards.
if(args){
if(args.label) {
this.label = args.label;
}
if(args.apikey) {
this._apikey = args.apikey;
}
}
this._cache = [];
this._prevRequests = {};
this._handlers = {};
this._prevRequestRanges = [];
this._maxPhotosPerUser = {};
this._id = dojox.data.FlickrRestStore.prototype._id++;
},
// _id: Integer
// A unique identifier for this store.
_id: 0,
// _requestCount: Integer
// A counter for the number of requests made. This is used to define
// the callback function that Flickr will use.
_requestCount: 0,
// _flickrRestUrl: String
// The URL to the Flickr REST services.
_flickrRestUrl: "http://www.flickr.com/services/rest/",
// _apikey: String
// The users API key to be used when accessing Flickr REST services.
_apikey: null,
// _storeRef: String
// A key used to mark an data store item as belonging to this store.
_storeRef: "_S",
// _cache: Array
// An Array of all previously downloaded picture info.
_cache: null,
// _prevRequests: Object
// A HashMap used to record the signature of a request to prevent duplicate
// request being made.
_prevRequests: null,
// _handlers: Object
// A HashMap used to record the handlers registered for a single remote request. Multiple
// requests may be made for the same information before the first request has finished.
// Each element of this Object is an array of handlers to call back when the request finishes.
// This prevents multiple requests being made for the same information.
_handlers: null,
// _sortAttributes: Object
// A quick lookup of valid attribute names in a sort query.
_sortAttributes: {
"date-posted": true,
"date-taken": true,
"interestingness": true
},
_fetchItems: function( /*Object*/ request,
/*Function*/ fetchHandler,
/*Function*/ errorHandler){
// summary: Fetch flickr items that match to a query
// request:
// A request object
// fetchHandler:
// A function to call for fetched items
// errorHandler:
// A function to call on error
var query = {};
if(!request.query){
request.query = query = {};
} else {
dojo.mixin(query, request.query);
}
var primaryKey = [];
var secondaryKey = [];
//Build up the content to send the request for.
var content = {
format: "json",
method: "flickr.photos.search",
api_key: this._apikey,
extras: "owner_name,date_upload,date_taken"
};
var isRest = false;
if(query.userid){
isRest = true;
content.user_id = request.query.userid;
primaryKey.push("userid"+request.query.userid);
}
if(query.apikey){
isRest = true;
content.api_key = request.query.apikey;
secondaryKey.push("api"+request.query.apikey);
}else if(content.api_key){
isRest = true;
request.query.apikey = content.api_key;
secondaryKey.push("api"+content.api_key);
}else{
throw Error("dojox.data.FlickrRestStore: An API key must be specified.");
}
request._curCount = request.count;
if(query.page){
content.page = request.query.page;
secondaryKey.push("page" + content.page);
}else if(typeof(request.start) != "undefined" && request.start != null){
if(!request.count){
request.count = 20;
}
var diff = request.start % request.count;
var start = request.start, count = request.count;
// If the count does not divide cleanly into the start number,
// more work has to be done to figure out the best page to request
if(diff != 0) {
if(start < count / 2){
// If the first record requested is less than half the
// amount requested, then request from 0 to the count record
count = start + count;
start = 0;
}else{
var divLimit = 20, div = 2;
for(var i = divLimit; i > 0; i--){
if(start % i == 0 && (start/i) >= count){
div = i;
break;
}
}
count = start/div;
}
request._realStart = request.start;
request._realCount = request.count;
request._curStart = start;
request._curCount = count;
}else{
request._realStart = request._realCount = null;
request._curStart = request.start;
request._curCount = request.count;
}
content.page = (start / count) + 1;
secondaryKey.push("page" + content.page);
}
if(request._curCount){
content.per_page = request._curCount;
secondaryKey.push("count" + request._curCount);
}
if(query.lang){
content.lang = request.query.lang;
primaryKey.push("lang" + request.lang);
}
var url = this._flickrRestUrl;
if(query.setid){
content.method = "flickr.photosets.getPhotos";
content.photoset_id = request.query.setid;
primaryKey.push("set" + request.query.setid);
}
if(query.tags){
if(query.tags instanceof Array){
content.tags = query.tags.join(",");
}else{
content.tags = query.tags;
}
primaryKey.push("tags" + content.tags);
if(query["tag_mode"] && (query.tag_mode.toLowerCase() == "any"
|| query.tag_mode.toLowerCase() == "all")){
content.tag_mode = query.tag_mode;
}
}
if(query.text){
content.text=query.text;
primaryKey.push("text:"+query.text);
}
//The store only supports a single sort attribute, even though the
//Read API technically allows multiple sort attributes
if(query.sort && query.sort.length > 0){
//The default sort attribute is 'date-posted'
if(!query.sort[0].attribute){
query.sort[0].attribute = "date-posted";
}
//If the sort attribute is valid, check if it is ascending or
//descending.
if(this._sortAttributes[query.sort[0].attribute]) {
if(query.sort[0].descending){
content.sort = query.sort[0].attribute + "-desc";
}else{
content.sort = query.sort[0].attribute + "-asc";
}
}
}else{
//The default sort in the Dojo Data API is ascending.
content.sort = "date-posted-asc";
}
primaryKey.push("sort:"+content.sort);
//Generate a unique key for this request, so the store can
//detect duplicate requests.
primaryKey = primaryKey.join(".");
secondaryKey = secondaryKey.length > 0 ? "." + secondaryKey.join(".") : "";
var requestKey = primaryKey + secondaryKey;
//Make a copy of the request, in case the source object is modified
//before the request completes
request = {
query: query,
count: request._curCount,
start: request._curStart,
_realCount: request._realCount,
_realStart: request._realStart,
onBegin: request.onBegin,
onComplete: request.onComplete,
onItem: request.onItem
};
var thisHandler = {
request: request,
fetchHandler: fetchHandler,
errorHandler: errorHandler
};
//If the request has already been made, but not yet completed,
//then add the callback handler to the list of handlers
//for this request, and finish.
if(this._handlers[requestKey]){
this._handlers[requestKey].push(thisHandler);
return;
}
this._handlers[requestKey] = [thisHandler];
//Linking this up to Flickr is a PAIN!
var handle = null;
var getArgs = {
url: this._flickrRestUrl,
preventCache: true,
content: content,
callbackParamName: "jsoncallback"
};
var doHandle = dojo.hitch(this, function(processedData, data, handler){
var onBegin = handler.request.onBegin;
handler.request.onBegin = null;
var maxPhotos;
var req = handler.request;
if(typeof(req._realStart) != undefined && req._realStart != null){
req.start = req._realStart;
req.count = req._realCount;
req._realStart = req._realCount = null;
}
//If the request contains an onBegin method, the total number
//of photos must be calculated.
if(onBegin){
var photos = null;
if(data){
photos = (data.photoset ? data.photoset : data.photos);
}
if(photos && typeof(photos.perpage) != "undefined" && typeof(photos.pages) != "undefined"){
if(photos.perpage * photos.pages <= handler.request.start + handler.request.count){
//If the final page of results has been received, it is possible to
//know exactly how many photos there are
maxPhotos = handler.request.start + photos.photo.length;
}else{
//If the final page of results has not yet been received,
//it is not possible to tell exactly how many photos exist, so
//return the number of pages multiplied by the number of photos per page.
maxPhotos = photos.perpage * photos.pages;
}
this._maxPhotosPerUser[primaryKey] = maxPhotos;
onBegin(maxPhotos, handler.request);
}else if(this._maxPhotosPerUser[primaryKey]){
onBegin(this._maxPhotosPerUser[primaryKey], handler.request);
}
}
//Call whatever functions the caller has defined on the request object, except for onBegin
handler.fetchHandler(processedData, handler.request);
if(onBegin){
//Replace the onBegin function, if it existed.
handler.request.onBegin = onBegin;
}
});
//Define a callback for the script that iterates through a list of
//handlers for this piece of data. Multiple requests can come into
//the store for the same data.
var myHandler = dojo.hitch(this, function(data){
//The handler should not be called more than once, so disconnect it.
//if(handle !== null){ dojo.disconnect(handle); }
if(data.stat != "ok"){
errorHandler(null, request);
}else{ //Process the items...
var handlers = this._handlers[requestKey];
if(!handlers){
console.log("FlickrRestStore: no handlers for data", data);
return;
}
this._handlers[requestKey] = null;
this._prevRequests[requestKey] = data;
//Process the data once.
var processedData = this._processFlickrData(data, request, primaryKey);
if(!this._prevRequestRanges[primaryKey]){
this._prevRequestRanges[primaryKey] = [];
}
this._prevRequestRanges[primaryKey].push({
start: request.start,
end: request.start + (data.photoset ? data.photoset.photo.length : data.photos.photo.length)
});
//Iterate through the array of handlers, calling each one.
dojo.forEach(handlers, function(i){
doHandle(processedData, data, i);
});
}
});
var data = this._prevRequests[requestKey];
//If the data was previously retrieved, there is no need to fetch it again.
if(data){
this._handlers[requestKey] = null;
doHandle(this._cache[primaryKey], data, thisHandler);
return;
}else if(this._checkPrevRanges(primaryKey, request.start, request.count)){
//If this range of data has already been retrieved, reuse it.
this._handlers[requestKey] = null;
doHandle(this._cache[primaryKey], null, thisHandler);
return;
}
var deferred = dojo.io.script.get(getArgs);
deferred.addCallback(myHandler);
//We only set up the errback, because the callback isn't ever really used because we have
//to link to the jsonFlickrFeed function....
deferred.addErrback(function(error){
dojo.disconnect(handle);
errorHandler(error, request);
});
},
getAttributes: function(item){
// summary:
// See dojo.data.api.Read.getAttributes()
return [
"title", "author", "imageUrl", "imageUrlSmall", "imageUrlMedium",
"imageUrlThumb", "link", "dateTaken", "datePublished"
];
},
getValues: function(item, attribute){
// summary:
// See dojo.data.api.Read.getValue()
this._assertIsItem(item);
this._assertIsAttribute(attribute);
switch(attribute){
case "title":
return [ this._unescapeHtml(item.title) ]; // String
case "author":
return [ item.ownername ]; // String
case "imageUrlSmall":
return [ item.media.s ]; // String
case "imageUrl":
return [ item.media.l ]; // String
case "imageUrlMedium":
return [ item.media.m ]; // String
case "imageUrlThumb":
return [ item.media.t ]; // String
case "link":
return [ "http://www.flickr.com/photos/" + item.owner + "/" + item.id ]; // String
case "dateTaken":
return [ item.datetaken ];
case "datePublished":
return [ item.datepublished ];
default:
return undefined;
}
},
_processFlickrData: function(/* Object */data, /* Object */request, /* String */ cacheKey){
// summary: Processes the raw data from Flickr and updates the internal cache.
// data:
// Data returned from Flickr
// request:
// The original dojo.data.Request object passed in by the user.
// If the data contains an 'item' object, it has not come from the REST
// services, so process it using the FlickrStore.
if(data.items){
return dojox.data.FlickrStore.prototype._processFlickrData.apply(this,arguments);
}
var template = ["http://farm", null, ".static.flickr.com/", null, "/", null, "_", null];
var items = [];
var photos = (data.photoset ? data.photoset : data.photos);
if(data.stat == "ok" && photos && photos.photo){
items = photos.photo;
//Add on the store ref so that isItem can work.
for(var i = 0; i < items.length; i++){
var item = items[i];
item[this._storeRef] = this;
template[1] = item.farm;
template[3] = item.server;
template[5] = item.id;
template[7] = item.secret;
var base = template.join("");
item.media = {
s: base + "_s.jpg",
m: base + "_m.jpg",
l: base + ".jpg",
t: base + "_t.jpg"
};
if(!item.owner && data.photoset){
item.owner = data.photoset.owner;
}
}
}
var start = request.start ? request.start : 0;
var arr = this._cache[cacheKey];
if(!arr){
this._cache[cacheKey] = arr = [];
}
dojo.forEach(items, function(i, idx){
arr[idx+ start] = i;
});
return arr; // Array
},
_checkPrevRanges: function(primaryKey, start, count){
var end = start + count;
var arr = this._prevRequestRanges[primaryKey];
return (!!arr) && dojo.some(arr, function(item){
return ((start >= item.start)&&(end <= item.end));
});
}
});
