I have a field in my website where I want users to enter book names that they can checkout from the database. I want it so that when they start typing the names I want suggestions or drop down under the input box matching the name of the book they are typing.
Is it possible to achieve something like this? I have a books table in my MySQL database and I am using Nodejs as my backend. I have searched a lot online but did not find anything related to this online. Therefore, I decided to ask the question here.
You have to send AJAX request with type GET and send the typed character to the Backend.
and in backend you have to do query for ex :select * from book where name like %input%
Then you have to return the result as an array to the front-end.
Finally, in your front-end code you have to render the result array under the input.
Also, you can use any ready jquery plugin to do this task in front-end code.
The UI element is commonly called a "typeahead" or autocomplete.
Twitter release their frontend component as a jQuery plugin called typeahead.js. Most frontend frameworks will have an equivalent plugin or component.
The backend datasource for the books is up to you to implement.
For small datasets you can render the required book data within the page so it is directly accessible from your javascript.
For large datasets you will probably need to create a backend "book search" service in Nodejs. Typeahead libraries can send that user input to a URL via an AJAX request and the service returns the matching results, usually as a JSON object.
Code for geek example for your stack.
You can make a drop-down menu with book names and using ajax you can get value from the input and search in database and display data .
I suggest you to use mongo db as database.
You can find tutorials in w3 schools or
in malayalam https://www.youtube.com/c/Crossroadstalk
I am working on a portal, where users can submit and retrieve data from a database via ajax and servlet responses.
My question is how should i not reveal the real ids of the database in the html DOM. To be more spesific, i need to know which is the best way for mapping between "real" and DOMS's ids, and if this should be happening on server or client side.
Thanks!
I think you would like to populate the doms with unique IDs to identify the element in the page. In that case there will be numerous ways.
easy one would be a Fancy value put in the dom like
dom_id = 'itu~#'+(your_id*1001)+'#rand()'
Then when requested you can retrieve your_id with the '#'separated and divide by 1001 .
OR
be more complex you may write any complex function
Happy coding.
I know it's a stupid question, but if I fill a form with various inputs but I don't give them a name and id, and I POST it to a php page, does the posted query contain any data?
If it does, then using inputs without names in a form result in a wasted sending time. am I right?
Is there any difference between GET and POST in this case?
I presume that the browser (client-side) determines what to send and what to not send.
I'll try to see what happens if i send a GET request: if in the browser bar appear something, some data has been sent.
But the POST method is still a mistery for me... when I have time I'll try to print the $_POST array. thanks for the "input" #MattP
I update my question after somebody attack: I printed down the result of $_POST and $_GET, but still, I think the only answer to my question is to check the weight of the data, not the things recognized by the server. If i send unnamed data to the server, the server may discard that ad take only the ones with the name.
(sorry for the bad english)
No, they won't get the data. id is optional, but for PHP to do anything it requires the name attribute.
I am trying to validate that a username is unique on a registration form and would like to verify the uniqueness of the username right after the client types it as opposed to performing this server side after the form has been submitted.
Should I collect a resultSet from the database, store it in an array and then pass this along to the jsp page in the form of a bean (I am using a model 2 design so the user passes through a servlet before arriving at the jsp page)? What if the array is very large? How do I bring this data into javascript?
Alternatively, is there a way to do the query using ajax and javascript all on the client side? Maybe its possible to somehow run the query in the background?
I am really just looking for some direction because I am clueless as to what to even begin researching something like this. Is this even a smart move, performance wise?
I'd use "AJAX" for this.
Here's one approach: set up a blur() handler on the username text field of your form. When the blur() method is invoked, you post the username to the backend code; it verifies it and returns some appropriate response. You then parse the response and change the CSS class on the username text field (e.g., turning it red) -- or do whatever else visually you want to do to indicate "username in use."
Either way, you've got to get the username from the client to the server for verification; you wouldn't want any mechanism which allowed the client to directly use the DB (think security/exploits/etc).
If you're not already familiar, check out jQuery (http://jquery.com/) to make your client-side life much easier.
Even if I offer alternatives to PUT and DELETE (c.f. "Low REST"), how can I provide user-friendly form validation for users who access my web service from the browser, while still exposing RESTful URIs? The form validation problem (described below) is my current quandry, but the broader question I want to ask is: if I go down the path of trying to provide both a RESTful public interface and a non-javascript HTML interface, is it going to make life easier or harder? Do they play together at all?
In theory, it should be merely a matter of varying the output format. A machine can query the URL "/people", and get a list of people in XML. A human user can point their browser at the same URL, and get a pretty HTML response instead. (I'm using the URL examples from the microformats wiki, which seem fairly reasonable).
Creating a new person resource is done with a POST request to the "/people" URL. To achieve this, the human user can first visit "/people/new", which returns a static HTML form for creating the resource. The form has method=POST and action="/people". That will work fine if the user's input is valid, but what if we do validation on the server side and discover an error? The friendly thing would be to return the form, populated with the data the user just entered, plus an error message so that they can fix the problem and resubmit. But we can't return that output directly from a POST to "/people" or it breaks our URL system, and if we redirect the user back to the "/people/new" form then there is no way to report the error and repopulate the form (unless we store the data to session state, which would be even less RESTful).
With javascript, things would be much easier. Just do the POST in the background, and if it fails then display the error at the top of the form. But I want the app to degrade gracefully when javascript support isn't available. At the moment, I'm led to conclude that a non-trivial web app cannot implement an HTML interface without javascript, and use a conventional RESTful URL scheme (such as that described on the microformats wiki). If I'm wrong, please tell me so!
Related questions on Stack Overflow (neither of which deal with form validation):
How to send HTML form RESTfully?
How do you implement resource "edit" forms in a RESTful way?
you could have the html form post directly to /people/new. If the validation fails, rerender the edit form with the appropriate information. If it succeeds, forward the user to the new URL. This would be consistent with the REST architecture as I understand it.
I saw you comment to Monis Iqbal, and I have to admit I don't know what you mean by "non-RESTful URLS". The only thing the REST architecture asks from a URL is that it be opaque, and that it be uniquely paired to a resource. REST doesn't care what it looks like, what's in it, how slashes or used, how many are used, or anything like that. The visible design of the URL is up to you and REST has no bearing.
Thanks for the responses. They have freed my mind a bit, and so in response to my own question I would like to propose an alternative set of RESTful URL conventions which actually embrace the two methods (GET and POST) of the non-AJAX world, instead of trying to work around them.
Edit: As commenters have pointed out, these "conventions" should not be part of the RESTful API itself. On the other hand, internal conventions are useful because they make the server-side implementation more consistent and hence easier for developers to understand and maintain. RESTful clients, however, should treat the URLs as opaque, and always obtain them as hyperlinks, never by constructing URLs themselves.
GET /people
return a list of all records
GET /people/new
return a form for adding a new record
POST /people/new
create a new record
(for an HTML client, return the form again if the input is invalid, otherwise redirect to the new resource)
GET /people/1
return the first record
GET /people/1/edit
return a form for editing the first record
POST /people/1/edit
update the first record
GET /people/1/delete
return a form for deleting the record
(may be simply a confirmation - are you sure you want to delete?)
POST /people/1/delete
delete the record
There is a pattern here: GET on a resource, e.g. "/people/1", returns the record itself. GET on resource+operation returns an HTML form, e.g. "/people/1/edit". POST on resource+operation actually executes the operation.
Perhaps this is not quite so elegant as using additional HTTP verbs (PUT and DELETE), but these URLs should work well with vanilla HTML forms. They should also be pretty self-explanatory to a human user...I'm a believer in the idea that "the URL is part of the UI" for users accessing the web server via a browser.
P.S. Let me explain how I would do the deletes. The "/people/1" view will have a link to "/people/1/delete", with an onclick javascript handler. With javascript enabled, the click is intercepted and a confirmation box presented to the user. If they confirm the delete, a POST is sent, deleting the record immediately. But if javascript is disabled, clicking the link will instead send a GET request, which returns a delete confirmation form from the server, and that form sends the POST to perform the delete. Thus, javascript improves the user experience (faster response), but without it the website degrades gracefully.
Why do you want to create a second "API" using XML?
Your HTML contains the data your user needs to see. HTML is relatively easy to parse. The class attribute can be used to add semantics as microformats do. Your HTML contains forms and links to be able to access all of the functionality of your application.
Why would you create another interface that delivers completely semantic free application/xml that will likely contain no hypermedia links so that you now have to hard code urls into your client, creating nasty coupling?
If you can get your application working using HTML in a web browser without needing to store session state, then you already have a RESTful API. Don't kill yourself trying to design a bunch of URLs that corresponds to someone's idea of a standard.
Here is a quote from Roy Fielding,
A REST API must not define fixed
resource names or hierarchies
I know this flies in the face of probably almost every example of REST that you have seen but that is because they are all wrong. I know I am starting to sound like a religious zealot, but it kills me to see people struggling to design RESTful API's when they are starting off on completely the wrong foot.
Listen to Breton when he says "REST doesn't care what [the url] looks like" and #Wahnfrieden will be along soon to tell you the same thing. That microformats page is horrible advice for someone trying to do REST. I'm not saying it is horrible advice for someone creating some other kind of HTTP API, just not a RESTful one.
Why not use AJAX to do the work on the client side and if javascript is disabled then design the html so that the conventional POST would work.