- 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/rpc/JsonRest.js
dojo.provide("dojox.rpc.JsonRest");
dojo.require("dojox.json.ref"); // this provides json indexing
dojo.require("dojox.rpc.Rest");
// summary:
// Provides JSON/REST utility functions
(function(){
var dirtyObjects = [];
var Rest = dojox.rpc.Rest;
var jr = dojox.rpc.JsonRest={
commit: function(kwArgs){
// summary:
// Saves the dirty data using REST Ajax methods
var data = [];
var left; // this is how many changes are remaining to be received from the server
kwArgs = kwArgs || {};
var actions = [];
var numDirty = dirtyObjects.length;
var alreadyRecorded = {};
for(var i = 0; i < numDirty; i++){
var dirty = dirtyObjects[i];
var object = dirty.object;
var append = false;
if(object && !dirty.old){
// new object
actions.push({method:"post",target:{__id:jr.getServiceAndId(object.__id).service.servicePath},
content:object});
}else if(!object && dirty.old){
// deleted object
actions.push({method:"delete",target:dirty.old});
}else{
// changed object
while(!(dojox.json && dojox.json.ref && dojox.json.ref.useRefs) && object.__id.match(/[\[\.]/)){ // it is a path reference
// this means it is a sub object and the server doesn't support directly putting to
// this object by path, we must go to the parent object and save it
var parentId = object.__id.match(/^[^\[\.]*/)[0];
if(parentId in alreadyRecorded){// if it has already been saved, we don't want to repeat it
continue;
}
// record that we are saving
object = alreadyRecorded[parentId] = Rest._index[parentId];
}
actions.push({method:"put",target:object,content:object});
}
data.push(object);
}
var xhrSendId;
var plainXhr = dojo.xhr;
left = actions.length;
var contentLocation;
// add headers for extra information
dojo.xhr = function(method,args){
// keep the transaction open as we send requests
args.headers = args.headers || {};
// the last one should commit the transaction
args.headers['X-Transaction'] = actions.length - 1 == i ? "commit" : "open";
if(contentLocation){
args.headers['Content-Location'] = contentLocation;
}
return plainXhr.apply(dojo,arguments);
};
for(i =0; i < actions.length;i++){ // iterate through the actions to execute
var action = actions[i];
dojox.rpc.JsonRest._contentId = action.content && action.content.__id; // this is used by LocalStorageRest
var isPost = action.method == 'post';
// send the content location to the server
contentLocation = isPost && dojox.rpc.JsonRest._contentId;
var dfd = action.deferred = Rest[action.method](
action.target,
dojox.json.ref.toJson(action.content,false,jr.getServiceAndId(action.target.__id).service.servicePath)
);
(function(object,dfd){
dfd.addCallback(function(value){
try{
// Implements id assignment per the HTTP specification
object.__assignedId = dfd.ioArgs.xhr.getResponseHeader("Location");
}catch(e){}
if(!(--left)){
dirtyObjects.splice(0,numDirty); // remove all the objects that were committed
if(kwArgs.onComplete){
kwArgs.onComplete.call(kwArgs.scope);
}
}
return value;
});
})(isPost && action.content,dfd);
dfd.addErrback(function(value){
// on an error we want to revert, first we want to separate any changes that were made since the commit
left = -1; // first make sure that success isn't called
var postCommitDirtyObjects = dirtyObjects.splice(numDirty,dirtyObjects.length - numDirty);
numDirty = 0; // make sure this does't do anything if it is called again
jr.revert(); // revert if there was an error
dirtyObjects = postCommitDirtyObjects;
if(kwArgs.onError){
kwArgs.onError();
}
return value;
});
}
// revert back to the normal XHR handler
dojo.xhr = plainXhr;
return actions;
},
getDirtyObjects: function(){
return dirtyObjects;
},
revert: function(){
// summary:
// Reverts all the changes made to JSON/REST data
while (dirtyObjects.length>0){
var d = dirtyObjects.pop();
if(d.object && d.old){
// changed
for(var i in d.old){
if(d.old.hasOwnProperty(i)){
d.object[i] = d.old[i];
}
}
for(i in d.object){
if(!d.old.hasOwnProperty(i)){
delete d.object[i];
}
}
}
}
},
changing: function(object,_deleting){
// summary:
// adds an object to the list of dirty objects. This object
// contains a reference to the object itself as well as a
// cloned and trimmed version of old object for use with
// revert.
if(!object.__id){
return;
}
//if an object is already in the list of dirty objects, don't add it again
//or it will overwrite the premodification data set.
for(var i=0; i<dirtyObjects.length; i++){
if(object==dirtyObjects[i].object){
return;
}
}
var old = object instanceof Array ? [] : {};
for(i in object){
if(object.hasOwnProperty(i)){
old[i] = object[i];
}
}
dirtyObjects.push({object: !_deleting && object, old: old});
},
deleteObject: function(object){
// summary:
// deletes an object
// object:
// object to delete
//
this.changing(object,true);
},
getConstructor: function(/*Function|String*/service){
// summary:
// Creates or gets a constructor for objects from this service
if(typeof service == 'string'){
service = new dojox.rpc.Rest(service,true);
}
if(service._constructor){
return service._constructor;
}
service._constructor = function(data){
// summary:
// creates a new object for this table
//
// data:
// object to mixed in
if(data){
dojo.mixin(this,data);
}
var idAttribute = jr.getIdAttribute(service);
Rest._index[this.__id = service.servicePath + (data[idAttribute] || (data[idAttribute] = Math.random().toString(16).substring(2,14)+Math.random().toString(16).substring(2,14)))] = this;
dirtyObjects.push({object:this});
// this._getParent(parentInfo).push(data); // append to this list
};
return dojo.mixin(service._constructor, service._schema, {load:service});
},
fetch: function(absoluteId){
// summary:
// Fetches a resource by an absolute path/id and returns a dojo.Deferred.
var serviceAndId = jr.getServiceAndId(absoluteId);
return this.get(serviceAndId.service,serviceAndId.id);
},
getIdAttribute: function(service){
// summary:
// Return the ids attribute used by this service (based on it's schema).
// Defaults to "id", if not other id is defined
var schema = service._schema;
var idAttr;
if(schema){
if(!(idAttr = schema._idAttr)){
for(var i in schema.properties){
if(schema.properties[i].unique){
schema._idAttr = idAttr = i;
}
}
}
}
return idAttr || 'id';
},
getServiceAndId: function(/*String*/absoluteId){
// summary:
// Returns the REST service and the local id for the given absolute id. The result
// is returned as an object with a service property and an id property
// absoluteId:
// This is the absolute id of the object
var parts = absoluteId.match(/^(.*\/)([^\/]*)$/);
var svc = jr.services[parts[1]] || new dojox.rpc.Rest(parts[1]); // use an existing or create one
return { service: svc, id:parts[2] };
},
services:{},
schemas:{},
registerService: function(/*Function*/ service, /*String*/ servicePath, /*Object?*/ schema){
// summary:
// Registers a service for as a JsonRest service, mapping it to a path and schema
servicePath = servicePath || service.servicePath;
servicePath = service.servicePath = servicePath.match(/\/$/) ? servicePath : (servicePath + '/'); // add a trailing / if needed
jr.schemas[servicePath] = schema || service._schema || {};
jr.services[servicePath] = service;
},
get: function(service, id, args){
// if caching is allowed, we look in the cache for the result
var deferred, result = args && args.useIndexCache && Rest._index[(service.servicePath || '') + id];
if(result && !result._loadObject){// cache hit
deferred = new dojo.Deferred();
deferred.callback(result);
return deferred;
}
deferred = service(id, args);
deferred.addCallback(function(result){
if(result.nodeType && result.cloneNode){
// return immediately if it is an XML document
return result;
}
return dojox.json.ref.resolveJson(result, {
defaultId: typeof id != 'string' || (args && (args.start || args.count)) ? undefined: id,
index: Rest._index,
idPrefix: service.servicePath,
idAttribute: jr.getIdAttribute(service),
schemas: jr.schemas,
loader: jr._loader
});
});
return deferred;
},
_loader: function(callback){
// load a lazy object
var serviceAndId = jr.getServiceAndId(this.__id);
var self = this;
jr.get(serviceAndId.service, serviceAndId.id).addBoth(function(result){
// if they are the same this means an object was loaded, otherwise it
// might be a primitive that was loaded or maybe an error
if(result == self){
// we can clear the flag, so it is a loaded object
delete result.$ref;
delete result._loadObject;
}else{
// it is probably a primitive value, we can't change the identity of an object to
// the loaded value, so we will keep it lazy, but define the lazy loader to always
// return the loaded value
self._loadObject = function(callback){
callback(result);
};
}
callback(result);
});
},
isDirty: function(item){
// summary
// returns true if the item is marked as dirty.
for(var i = 0, l = dirtyObjects.length; i < l; i++){
if(dirtyObjects[i]==item){return true;}
}
return false;
}
};
})();
