I have a shopping cart which I am maintaining with Ngrx and for maintaining the persistence of the state after a page refresh I have two options:
Stringify the state and store it in local storage and get it back after the reload.
Stringify the state and store it inside a text file and then get the string out of the file and use JSON.parse to convert the string back to a JSON object.
I am storing some price related data so didn't want to store in local storage.
What should I use? Or is there any better way to do this?
Using the following library you can achieve your desired result
https://www.npmjs.com/package/ngrx-store-localstorage
I am using it myself in multiple projects and it works great, it acts as a meta reducer and therefore 'automatically' takes care of things for you.
https://ngrx.io/guide/store/metareducers
You can use the ngrx-store-localstorage package as https://stackoverflow.com/a/58362198/10112124 mentioned, or write your custom meta-reducer or as you mentioned use effects to do this. For the latter, Tomas Trajan has an example in his angular-ngrx-material-starter project.
All the above options are find, but I wanted to give an answer on what to store
I am storing some price related data so didn't want to store in local storage.
If you have sensitive information, you could store it in the sessions storage - when the session is ended, the storage will be cleaned up.
You shouldn't have to store sensitive information, why don't you store important information like the article id and the quantity? This way you can rehydrate the store with this information, and build up your shopping cart with this information plus the products of the catalog you would load in a normal way.
Related
I have about 10GB worth of data that I would like to import to Parse. the data is currently in JSON format which is great for importing data using the parse importer.
However I have no unique identifier to these objects. Of course they have unique properties e.g. a url, the ids pointing to specific objects need to be constant.
What would be the best way to edit the large amount of data -in bulk- on their server without running into request issues (as I'm currently on the free pricing model) and without taking too much time to alter the data.
Option 1
Import the data once and export the data in JSON with the newly assigned objectIds. Then edit them locally matching the url then replace the class with the new edited data. Any new editions will receive a new objectId by Parse.
How much downtime between import and export will there be as I would need to delete the class and recreate it? Are there any other concerns with this methodology?
Option 2
Query for the URL or array of URLs and then edit the data then re-save. This means the data will persist indefinitely but as the edit will consist of hundreds of thousands of objects will this most likely over run the request limit?
Option 3
Is there a better option I am missing?
The best option is to upload to Parse then edit through their normal channels. Using various hacks it is possible to stay below the 30pings/second offered as part of the free tier. You can iterate over the data using background jobs (written in Javascript) -- you may need to slow down your processing so you don't hit limits. The super hacky way is to download from the table to a client (iOS/Android) app and then push back up to Parse. If you do this in batch (not a synchronous for loop, by the way), then the latency alone will keep you under the 30ping/sec limit.
I'm not sure why you're worried about downtime. If the data isn't already uploaded to Parse, can't you upload it, pull it down and edit it, and re-upload it -- taking as long as you'd like? Do this in a separate table from any you are using in production, and you should be just fine.
I've got a raspberry pi with raspbian and all I've done is installed apache2 and created a small web site i want to create a database.
is this possible without using mysql or other database software. i want to use .JS or a text based database
I want to be able to save the contact details in a text format.
can someone point me in the right direction a simple example would be appreciated all online research wants mysql etc
all i want is a simple example as in enter name and submit i want that name to be logged so if name entered again it will say welcome back once i know this mechanism i can add all the other fields. The reason i want this format is so i can see the list that I'm creating.
i just can't get to grips with mysql I've spent months trying to understand mysql but its just not going in so want to simplify the database to minimal workings so i can complete my site. I know .Js isn't so secure but its a demo so security not important at this point any help appreciated
It would be possible to use JSON for your data storage. It will be a key-value storage. On each page view you will have to load the entire file into memory and parse it. From then on it is possible to loop it to search data or get data from a key. This requires no extra software just PHP with Apache.
How to:
Build an array, use json_encode to create the JSON and save it using file_put_contents(). Remebmer to save the whole array and not just the newly added element.
This is not a relative database but might do the trick if you build an intelligent system with cookie's to store an ID that is associated with a user.
Alternative you could use serialize() instead of json;
If you don't mind to use different way of storing data you can use either Google App Engine or mongolab or other cloud based databases
Can someone tell me if we can bind localStorage objects to the ui using Knockout.js or some other javascript framework?
What I want is - as the user loads up the page he gets the latest version of data from the local storage (Using some framework) and then I keep polling my service to see if there is any change in the data. If there is change I will update the local storage with the fresh data and make the ui update automatically (Using some framework).
This complete flow is required to be done with minimum amount of code.
This might be too early to post since I have not researched much my self about how to go about it. Any help or redesign in terms of architecture is appreciated.
I would suggest writing some code that checks if there is new data from your ajax service. If so, grab it, store it in a model which is in your viewmodel already bound to your UI. Also, save that model to localStorage.
If the data is not new, grab it from localStorage, put it in your model (that is in your viewmodel), and you are done.
I'm interested in building a small offline webapp and I'm looking for some advice. Here's the basics of what I want it to do
Create reports that, initially, will just have a name and text field
List, edit, and delete these notes
Ideally I'd like to add more fields to the reports later
Is localstorage a good option for storing this type of data locally? If so, can anybody direct me to a complete list of the commands for interacting with it in javascript? e.g. setItem, getItem, etc.
Thanks.
localstorage will work just fine for this, but don't think of it as a robust solution.. It's just a basic key/value store and won't be very performant with thousands of complex things going on.
Check out the excellent Dive into HTML5 guide on localstorage:
http://diveintohtml5.info/storage.html
Link to the localstorage apis
Yes localstorage would be perfect for you application. It would allow your application to have no need to connect to a server at all. Keep in mind that local storage does have maximums on the amount of data that can be stored.
EDIT:
Using JSON.stringify() on can convert complex javascript objects to json which can be storage and retrieved with ease inside of local storage.
I'm building medium sized business web application, data is being saved on a MySQL database.
I'm trying to think of a way of adding certain selectable "widgets" to that application (e.g. a currency widget - which will show user specified currencies when the web app is visible) but having an hard time deciding how to save the widget data and settings per user since the widgets do not have a common base.
For example, the currency widget's settings is totally different than say, a weather widget.
One will require a list of desired currencies, and one would require the weather's target location.
I thought of solving the above by keeping all the widget's settings data encoded in the "widgetData" column of a db table which will contain the userId, widgetId and widgetData.
I chose JSON as my way of encoding, and each time a user tries to load it's page, I have to decode it's settings and hand the user the desired data based on the settings.
The same is true for saving the widget's actual data which does not have a common base itself.
Hopefully I can solve this by using a NO-SQL data structure next time, but this is not the case for the current project.
The Entity Attribute Value database model would be useful very to you in this scenario.
It's much more flexible than JSON or XML or other types of formats because it works within your standard SQL data storage, albeit in a different manner.
I voted up the EAV solution because this is one of the valid reasons for using it, but don't fall in love with it. An advantage of EAV is that it is database-native to the extent that you can write queries in SQL to query it (find me all widgets missing some setting and then add it), while most engines do not have JSON support.
On the other hand, if you want/need to query within a column which contains structured data, XML is a better option than JSON (right now): http://dev.mysql.com/doc/refman/5.1/en/xml-functions.html#function_extractvalue
If your widgets are rendered via Javascript in the browser, then your solution is perfectly fine. Your widgetData remains a JSON string, in Javascript you use JSON.parse() to turn it into an object and render it, and JSON.stringify() to turn it back into a string before posting it back to your server.