How to retrieve query parameter in Server Script - mobile

Question

I'm using Windows Azure Mobile Service to build the backend for my app. For server script's read operation, now I want to retrieve the query parameter like $filter, $select in the script, etc. Any idea?

Answer 1

After hacking around with the 'query' object in the 'read' function's parameter (by using console.log ), I finally found the solution:
function isObject(variable) {
return variable !== null &&
variable !== undefined &&
typeof variable === 'object';
}
// Find all the member-value pairs from the expression object
function findMemberValuePairsFromExpression (expr, ret) {
if (!isObject(expr)) {
return null;
}
ret = ret || {};
for (var name in expr) {
if (expr.hasOwnProperty(name)) {
var prop = expr[name];
if (name === 'parent') { // Ignore parent property since it's added by us
continue;
}
else if (name === 'left') { // member expression are in the left subtree
if (isObject(prop)) {
prop.parent = expr; // Remember the parent
findMemberValuePairsFromExpression(prop, ret);
}
}
else if (name === 'member') {
// Found a member expression, find the value expression
// by the knowledge of the structure of the expression
var value = expr.parent.right.value;
ret[prop] = value;
}
}
}
if (expr.parent) {
// Remove the added parent property
delete expr.parent;
}
return ret;
}
// Get the filters component from query object and
// find the member-value pairs in it
function findMemberValuePairsFromQuery (query) {
var filters = query.getComponents().filters;
return findMemberValuePairsFromExpression(filters);
}
function read (query, user, request) {
request.execute();
}
Remember that this approach heavily relies on the inner structure of the query object so it may break in the future.
query.getComponents() also returns other parts of the query, like 'select', 'skip', 'top', etc. Basically anything of the oData protocol