Is it possible to pass multiple parameters in request url using webhdfs? - hadoop

Is it possible to pass multiple arguments in url using webhdfs for instance like show below? http://112.128.0.17:9870/webhdfs/v1/user/myuser/file2.txt&file1.txt?op=DELETE&user.name=myuser&createflag=&createparent=true&overwrite=false&recursive=trueObviously it is just an example which doesn't work but maybe there is any way to do this? Or it is needed to send multiple requests?

The answer is no, besides the fact that the URL you created is not even valid.
You will need to issue one request (file operation) at a time.

Related

Is it necessary to use the form to transfer data to the server?

I'm new to backend programming. I chose the laravel framework. Already learned the basics. During the study, the question arose: is it necessary to use the form to transfer data to the server ?. For example: the deletion route looks like this to me
Delete.
If I leave it, will it be a mistake? Maybe advise an article or something. Thanks in advance
Short answer is no, it's not necessary, but you should (if you're bound to HTML only).
The HTTP standard has different methods for different purposes. Using an anchor tag will always make a HTTP GET request to the link/server, which is not ideal, GET request should never change the remote (server) state, that's a job other methods (POST, PUT, DELETE, PATCH), you should try to use the method that better describe what you're trying to do: in your case I suppose you're trying to delete a complaint, so a DELETE or POST is what you're looking for.
The only way to use make a non GET request in plain HTML* is to use <form>. Also if you're planning to use a method different from POST you should take a look at Laravel's #method here
Mind that if you can and want to use JavaScript to perform your request you totally can, dropping the requirement to have use form (docs and docs).

Standart/common/right way to send data in API request

I'm trying to learn how to create an API (I use Laravel in the backend and Postman to send requests), but I have a basic doubt when sending data to be processed in the backend.
I see that there are several ways to send data to the backend, but I'm not sure which is the right way to do it.
For example, with Postman I have seen that the sending can be done as parameters through the URI:
www.example.com/api/v1/orders?limit=10&offset=20
I can also do it in the body of the request through the tags
form data
x-www-form-urlencoded
raw
other ...
I understand that I can make the request along with sending data in several ways. I would like to know what should be the correct, standard or optimal way to do it for usual requests such as getting a series of records with a filtering, an order or a pagination.
I would also like to know if the way of sending data should depend on the verb to be used in the request.
My main question/problem is that I would like the way users use the API to be as simple or suitable as possible for them. I'm clear that I want to always return the data (when necessary) in JSON format but I'm not clear on how it should be sent.
Please, could someone clarify these doubts (maybe a link to a page where this kind of doubts are dealt with).
Thank you very much in advance.
It depends:
GET, HEAD and DELETE don't have a request body so all parameters have to be send via URL
POST can be easily sent via form data in Laravel
For PUT/PATCH I prefer application/json because PHP sends it via php://input stream which can have some problems in Laravel sometimes
You can also combine URL parameters and the request body. Compound types (for example models) can only be send as one via request body while it might suffice to send an id via URL parameter.
I guess, nearly more important is the overall format and documentation. The format should be consistent, easy to understand and maybe standardized (for example: https://jsonapi.org/format/#crud).
Keep in mind that forms do two things by default:
Only having methods GET and POST
Only having ectypes application/x-www-form-urlencoded, multipart/form-data and text/plain
If you want to enforce something else, you have to use scripts/libraries to do this.
Nowadays, it appears that JSON content (for POST, PUT, and PATCH) is the most popular and readable. It is well recognizable and clean. Examples in the documentation are easy to read.
I would go for JSON for both, incoming parameters and the outgoing response. This regards parameters related to the business logic of your application.
At the same time, for GET, HEAD, and DELETE methods, you don't have a payload at all. For parameters related to controlling the API (i.e. not strictly related to the business logic of the application, but to the API itself) I'd go for query parameters. This applies to parameters like limit, offset, order_by, etc.
P.S. There is only one caveat related to the JSON format. If your API happens to have file parameters you may face the problem. You can still use JSON format, but in such a case, you should encode your files (e.g. using base64) and put it as string parameters of your JSON. This may be demanding for the consumers of your API ;) This will also enlarge your files and will probably force you to process these files in memory. The alternative is to use multipart/form-data as a request Content-Type - this way you can have both, the form and separate "space" for files. It's worth keeping this case in mind when you decide.

I need to convert any string without GET parameters

I need to convert any string without GET parameters:
www.mysite.com/?a=5&s=5 ---> www.mysite.com/
www.mysite.com/books/?bla=blabla&bla=4 ---> www.mysite.com/books/
I need to hide $_GET parameters.
I cant use POST parameters.
How can i do this ?
Then use POST.
POST-Data is not visible in the url and can be used like GET, but has to be pushed from a HTML-Form or something
Variables submitted by the method GET go in the URL, so it's impossible to hide them. However, you can make them prettier using the MVC architectural pattern. It's a more sofisticate solution that really pays off, in terms of organization.
For example, URLs like mysite.com/?a=5&s=5 would become mysite.com/5/5
You used $_GET[], so I assume you're using PHP. Take a look at Laravel or Phalcon.
In case you do not want to show any of the variables, you have to use POST. Data submitted by POST is inserted in the body of the HTTP request. Please, keep in mind that the body will not be encrypted, unless you use HTTPS.

Asp.Net Web Api - Change parameter name

In my team we have coding rule that requires that every function's parameter starts with prefix, e.g. *p_someParam*.
With Web Api if we want to request a GET function that takes two parameters, we should add those parameters like "...?p_firstParam=value1&p_secondParam=value2".
Is there some way to use in requests more user-friendly names, like someParam without prefix, that will automatically map to parameters in controller's action? Maybe there is some attribute to rename action parameters? I couldn't find any similar example.
Every clue is appreciated.
I think you looking for URL rewriting, in that you need to map the urls to config or programmatic
http://www.codeproject.com/Articles/2538/URL-Rewriting-with-ASP-NET nice article to follow, its in ASP.Net,

GET vs POST in AJAX?

Why are there GET and POST requests in AJAX as it does not affect page URL anyway? What difference does it make by passing sensitive data over GET in AJAX as the data is not getting reflected to page URL?
You should use the proper HTTP verb according to what you require from your web service.
When dealing with a Collection URI like: http://example.com/resources/
GET: List the members of the collection, complete with their member URIs for further navigation. For example, list all the cars for sale.
PUT: Meaning defined as "replace the entire collection with another collection".
POST: Create a new entry in the collection where the ID is assigned automatically by the collection. The ID created is usually included as part of the data returned by this operation.
DELETE: Meaning defined as "delete the entire collection".
When dealing with a Member URI like: http://example.com/resources/7HOU57Y
GET: Retrieve a representation of the addressed member of the collection expressed in an appropriate MIME type.
PUT: Update the addressed member of the collection or create it with the specified ID.
POST: Treats the addressed member as a collection in its own right and creates a new subordinate of it.
DELETE: Delete the addressed member of the collection.
Source: Wikipedia
Well, as for GET, you still have the url length limitation. Other than that, it is quite conceivable that the server treats POST and GET requests differently; thus the need to be able to specify what request you're doing.
Another difference between GET and POST is the way caching is handled in browsers. POST response is never cached. GET may or may not be cached based on the caching rules specified in your response headers.
Two primary reasons for having them:
GET requests have some pretty restrictive limitations on size; POST are typically capable of containing much more information.
The backend may be expecting GET or POST, depending on how it's designed. We need the flexibility of doing a GET if the backend expects one, or a POST if that's what it's expecting.
It's simply down to respecting the rules of the http protocol.
Get - calls must be idempotent. This means that if you call it multiple times you will get the same result. It is not intended to change the underlying data. You might use this for a search box etc.
Post - calls are NOT idempotent. It is allowed to make a change to the underlying data, so might be used in a create method. If you call it multiple times you will create multiple entries.
You normally send parameters to the AJAX script, it returns data based on these parameters. It works just like a form that has method="get" or method="post". When using the GET method, the parameters are passed in the query string. When using POST method, the parameters are sent in the post body.
Generally, if your parameters have very few characters and do not contain sensitive information then you send them via GET method. Sensitive data (e.g. password) or long text (e.g. an 8000 character long bio of a person) are better sent via POST method.
Thanks..
I mainly use the GET method with Ajax and I haven't got any problems until now except the following:
Internet Explorer (unlike Firefox and Google Chrome) cache GET calling if using the same GET values.
So, using some interval with Ajax GET can show the same results unless you change URL with irrelevant random number usage for each Ajax GET.
Others have covered the main points (context/idempotency, and size), but i'll add another: encryption. If you are using SSL and want to encrypt your input args, you need to use POST.
When we use the GET method in Ajax, only the content of the value of the field is sent, not the format in which the content is. For example, content in the text area is just added in the URL in case of the GET method (without a new line character). That is not the case in the POST method.

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