Hello is this code in the comment possible with Parse Cloud Code?
Parse.Cloud.beforeFind('Note', function(req) {
var query = req.query;
var user = req.user;
// if a given 'Note' visibility is set to 'Unlisted'
// return only the Notes with 'user' field that the calling _User
});
The documentation only shows how to filter fields that are returned but not exactly remove items from the query result in the Cloud Code.
This can be done through ACL, I know, but the caveat is that if the request is a retrieve function and not query the Note should still return.
Assuming you've saved the user as an object relationship (not a string id). Just add the qualification you need, such as:
query.equalTo("your_user_pointer_col_on_Note", user)
We need to update the all the documents in a collection to change their shape. We'd like to record an audit of the change in a different collection where we will store a document which contains the old and new version. In order to make this change atomic, we are using a stored proc.
The issue we are facing is updating another collection from a stored proc. It seems the audit document is always written into the collection the stored proc belongs to.
I have written up a sample stored proc:
function sample(prefix) {
var context = getContext();
var fooCollection = context.getCollection();
var barCollection = context.getCollection("BarCollection");
// Query documents and take 1st item.
var isAccepted = fooCollection.queryDocuments(
fooCollection.getSelfLink(),
'SELECT * FROM root r',
function (err, feed, options) {
if (err) throw err;
// Check the feed and if empty, set the body to 'no docs found',
// else take 1st element from feed
if (!feed || !feed.length) context.getResponse().setBody('no docs found');
else {
var fooDoc = feed[0];
var barDoc = {
"foo" : fooDoc,
"bar" : "bar"
}
var isAccepted2 = barCollection.createDocument(barCollection.getSelfLink(), barDoc);
if (!isAccepted2) throw new Error('The query was not accepted by the server.');
}
});
if (!isAccepted) throw new Error('The query was not accepted by the server.');
}
In this sample, my stored proc is saved in the FooCollection. I get a document and try to save a copy into the BarCollection. The new document is always saved into the FooCollection.
Is this scenario supported in Document DB? If so, what changes do I need to make the stored proc to make it work?
DocumentDB stored procedures are collection-scoped. You will not be able to write audit info to a separate collection; you'd need to write to the same collection.
Currently I have got given stored procedure
function getData() {
var context = getContext();
var collection = context.getCollection();
var output = collection.map(function (doc) {
return {
id: doc.id,
name: doc.name,
status: doc.status,
description: doc.description,
owner: doc.owner
}
})
return JSON.stringify(output)
}
Issue here is that it only returs 7 documents (matching what you get when you not get 'load' action on azure panel) and is skipping rest of the collection.
I believe that it can be fixed with using SQL query syntaxt but I would like to know how can I query all documents in the collection without using it.
Try adding a FeedCallback like shown here and make the signature of the callback be function(error, resources, options). Look for errors. Also inspect the options parameter for a continuation. If that fails to give you enough information to fix the problem, then you might want to consider a more traditional query and transformation approach not using collection.map().
I am new to Web SQL database and I use it to save data in a local database in a web page.
I can create a database by
var db = openDatabase('database', '1.0', 'my database', 2 * 1024 * 1024);
and I can create a table by doing this
db.transaction(function (tx) {
tx.executeSql('CREATE TABLE IF NOT EXISTS mytable (blah,blah)');
});
I can delete the table by
db.transaction(function (tx) {
tx.executeSql('DROP TABLE mytable');
});
but is there a way to delete the database programmatically?
Using PersistenceJS there is a persistence.reset API which will wipe the database clean.
PersistenceJS Site
For developing / testing purposes, you can view content and delete webSQL, IndexedDB, cookies, etc by searching for your domain name at this URL in Chrome:
chrome://settings/cookies
There, you can delete all the storage for a domain or just certain local storage entities. Yes, the URL implies just 'cookies', but the interface at this URL includes all types of offline storage.
It would be great I think if the Chrome developer tools interface had the ability to right-click and delete a data storage entity in the Resources tab along with inspecting the content. But for now, all I know of is the settings/cookies URL.
Spec says:
4.1 Databases
Each origin has an associated set of databases. Each database has a name and a current version. There is no way to enumerate or delete the databases available for an origin from this API.
I am developing a phonegap+jquery-mobile+KO app with offline storage using web sql via persistencejs, and jasmine js for BDD.
I'm working on some sort of "database cleaner" to be executed after each spec. When I was searching on how to drop a web sql database I read the reply https://stackoverflow.com/a/10929725/667598 (in this thread/question), and went to see what's in that directory (Mac OS X).
cd ~/Library/Application\ Support/Google/Chrome/Default/databases
Inside you will see a Databases.db SQLite3 database, and directories for each origin. These directories are named with the pattern protocol_host_somenumber (I don't know what that number is). So for example, in my case, since my apps are just files I open in Google Chrome with the file:/// … protocol, I can see a file__0 directory. And for twitter and I can also see a http_twitter.com_0 and a https_twitter.com_0.
Inside this directories all file names are just numbers. For example inside file__0 I found a file named 8 and another named 9. In my case, these files are websql database. I don't know if there also Indexed DB databases in chrome's Default/databases dir.
With this names it is a little hard to guess what database is what. You can open the database and you'll have to infer the app or site via its tables and data.
Luckily, the Databases.db I mentioned before is a mapping between those files named with numbers and the databases.
You can open the Databases.db and any other web sql file with the sqlite3 command
sqlite3 Databases.db
Obviously, once inside the sqlite3 shell, is handy to have some SQL knowledge. Anyway, it is also always handy some help, which is available via the command
.help
With the command .tables you can list tables in the database. Inside this Databases.db we can find the tables Databases and meta. The important one is Databases, so with a
select * from Databases;
we can see the mapping between the databases and their files. For example
7|http_jquerymobile.com_0|testdb|html5 test db|200000
8|file__0|elfaro_dev|Base de datos de ElFaro para desarrollo|734003200
The first column is the id of the table which is the number used for db file names, the second is the origin (the directory) the other columns are the db name, the db description and the estimated size used when creating the db from the Javascript API.
So to actually delete a database what I did was to delete it from this table, for example:
delete from Databases where id = 8
And then delete the actual file from the filesystem (outside sqlite3 shell)
rm file__0/8
And that's it.
PS: I know this is a too long answer for a simple subject but I just needed to flush this from my system and back it up somewhere like SO or a blog.
The developer options
There is no way to enumerate or delete the databases programmatically (yet).
Chrome developers can navigate to chrome://settings/cookies search and delete any database
Opera developers can navigate to opera://settings/cookies
The only way to truly delete a database (and everything else)
A new Spec says this might be possible in the feature with both response header and javascript.
The disadvantages is that you can't control what is being deleted, So you would need to create a backup first of everything else unless you want to clear everything
2.1.3. The storage parameter
The storage parameter indicates that the server wishes to remove locally stored data associated with the origin of a particular response’s url. This includes storage mechansims such as (localStorage, sessionStorage, [INDEXEDDB], [WEBDATABASE], etc), as well as tangentially related mechainsm such as service worker registrations.
Js:
navigator.storage.clear({
types: [ "storage" ],
includeSubdomains: true // false by default
});
Response header:
res.header("Clear-Site-Data", "storage; includeSubdomains");
But this is not avalible to any browser yet...
Best solution for clients (not the developers)
/* This will fetch all tables from sqlite_master
* except some few we can't delete.
* It will then drop (delete) all tables.
* as a final touch, it is going to change the database
* version to "", which is the same thing you would get if
* you would check if it the database were just created
*
* #param name [string] - the database to delete
* #param cb [function] - the callback when it's done
*/
function dropDatabase(name, cb){
// empty string means: I do not care what version, desc, size the db is
var db = openDatabase(name, "", "", "");
function error(tx, err){
console.log(err);
}
db.transaction(ts => {
// query all tabels from sqlite_master that we have created and can modify
var query = "SELECT * FROM sqlite_master WHERE name NOT LIKE 'sqlite\\_%' escape '\\' AND name NOT LIKE '\\_%' escape '\\'";
var args = [];
var success = (tx, result) => {
var rows, i, n, name;
rows = result.rows;
n = i = rows.length;
// invokes cb once it’s called n times
function after(){
if (--n < 0) {
// Change the database version back to empty string
// (same as when we compear new database creations)
db.changeVersion(db.version, "", function(){}, error, cb);
}
}
while(i--){
// drop all tabels and calls after() each time
name = JSON.stringify(rows.item(i).name);
tx.executeSql('DROP TABLE ' + name, [], after, error);
}
// call it just 1 more extra time incase we didn't get any tabels
after();
};
ts.executeSql(query, args, success, error);
});
}
Usage
dropDatabase("database", function(){
console.log("done")
});
The localdatabase files are stored in your Windows user settings under Application Data > Google > Chrome > User Data > Default > databases.
So manually deleting them is theoretically possible. This is only useful while testing / developing on your own computer, since when another user opens your app/site, it is unlikely to have file system access.
However, even though you can find the files and delete them, the data sticks around. I've tried it with Chrome both open and closed and all chrome processes ended, and yet the browser inspector keeps showing me my old database with all the unwanted fields and data in it.
This is answered in HTML5 database storage (SQL lite) - few questions.
To summarize:
Currently no way to drop a WebSQL database.
Probably use Indexed DB or localStorage instead.
In my library implementation, I just delete all tables. Which, indeed, delete the database. List of tables are select * from sqlite_master.
Please note that if you use multiple
tx.executeSql('DROP TABLE mytable');
statements in the same transaction callback then make sure that they all exist or consider using DROP TABLE IF EXISTS syntax instead. If even one table doesn't exist when you try to drop it will result in the entire transaction failing. This failure results in a rollback of the transaction and means that the data will stay in your database even when you thought that it should have been deleted. There is no error reported unless you're specifically listening for it in the executeSql's 4th argument which is an error callback. This is intended behavior but is, in my experience, confusing.
No method to delete the existing database in websql it will clear when the cache is cleared or
The browser is closed. If you want to create a database with the same name Just use openDatabase Method It will first check for the existence of the database with the same name. If not exists it will create one otherwise it will open the existing one
please follow this link http://html5doctor.com/introducing-web-sql-databases/
I have code that, when a user is logged in, selects recipes that apply to him based on the ingredients (items) he has previously identified identified as possessions.
This code gets the id's of the items the user already has:
if request.user.is_authenticated():
user_items = [possession.item for possession in request.user.possession_set.all()]
user_items_ids = [item.id for item in user_items]
uids = set(user_items_ids)
The following code, which already existed, is where I run into problems...
recipes = [(recipe, len(set([item.id for item in recipe.items.all()]) & uids), recipe.votes) for recipe in recipes]
I created another part of the site that allows people who have not yet signed up to just pick a few ingredients. I do this with some jQuery on the front end, then send the results to the backend:
var ingredient_set = [];
$('.temp_ingredient').each(function(index){
ingredient_set[index] = $(this).attr('id').substr(4);
});
$.get('/recipes/discover', { 'ingredients': ingredient_set },
function(){
alert("Success");
});
The problem is when I receive them on the Django side, with this code:
uids = request.GET['ingredients']
I get the following error:
unsupported operand type(s) for &: 'set' and 'unicode'
Basically, I know they aren't in the same format, but I don't know how to get them to be compatible.
You are sending a JavaScript array in the query string of your GET request. Therefore you should use request.GET.getlist. Just using request.GET[key] gives you the last value for that key.
>> request.GET['foo[]']
u'5'
>> request.GET.getlist('foo[]')
[u'1', u'2', u'4', u'5']
Note that the values are unicode, but you probably need them as integers, so be sure to convert them.
uids = request.GET.getlist('foo[]')
uids = set([int(x) for x in uids])
I'm not sure why my key is actually foo[] and not just foo, but as you get no KeyError, request.GET.getlist('ingredients') should work.