I have an web API application that will serve many clients at different times of release and now i need to implement a versioning. Because the API code will be constantly updated and API users will not be able to instantly change their API. Well, the standard situation is when you need to introduce versioning in general. I'm finding a way to organize it inside my API. It's clear that it will not be different folders with an application on the server, conditionally called app_v1, app_v2, app_v2.1, etc., cause this is duplication, redundancy and bad practise.
It's look like will be one application, and in the controllers at the code level there will be a division of the logic already, like If(client_version==1) do function1() else if(client_version==2) do function2(), etc. It seems that git supports tags, this is something similar to versioning, but because all supported versions of the application need be on the server at the same time, this is not about that. how i can realize an architecture in this case?
There are many well-known ways to use API versioning to make code work with older versions. (backward compatibility). The general purpose of API versioning is a way to make sure that different clients can use different versions of an API at the same time. I've seen several ways to do API versioning, such as:
URL Path Versioning: In this method, the number of the version is part of the API endpoint's URL path. For instance:
https://api.example.com/v1/assets
https://api.example.com/v2/assets
URL Query String Parameter: In this method, the version number is added to the API endpoint's URL as a query string parameter. For instance:
https://api.example.com/assets?version=1
https://api.example.com/assets?version=2
HTTP Header: In this method, the version number is put in an HTTP header, like the Accept-Version header. For instance:
Accept-Version: 1
Accept-Version: 2
If you are using dotnet for you project I would like recommend to standard library for that recommend to check this out. Or you can find solid materials in term of WebApi Versioning following link by #Steve Smith.
There is another answer.
Related
I am planning to have these endpoints for our REST APIs.
PUT /tenant/:tenantId/users/save/:username
POST /tenant/:tenantId/users/invite
GET /tenant/:tenantId/users/fetch
GET /tenant/:tenantId/users/fetch/:username
PATCH /tenant/:tenantId/users/activate/:username
POST /tenant/:tenantId/groups/save/
Verbs such as save/fetch/activate are from the consistency point of view. Are these RESTFul according to the REST principles? How should these be changed if at all? Any recommendations?
According to this REST Resource Naming Guide:
RESTful URI should refer to a resource that is a thing (noun) instead of referring to an action (verb) because nouns have properties which verbs do not have – similar to resources have attributes.
And also
URIs should not be used to indicate that a CRUD function is performed. URIs should be used to uniquely identify resources and not any action upon them. HTTP request methods should be used to indicate which CRUD function is performed.
So let's take your first URI as example
PUT /tenant/:tenantId/users/save/:username
Here you are using the verb save. As mentioned before you should not be indicating a CRUD operation in the URI, in this case using a POST would be more appropriate.Here is a guide with the purpose of each HTTP verb. Knowing this, I think that for example a more appropriate URI for that case would be something like
POST /tenants/:tenantId/users/:username
In this cases:
GET /tenant/:tenantId/users/fetch
GET /tenant/:tenantId/users/fetch/:username
you should remove the fetch because you are already telling through the GET verb that data is being fetched. Same goes for the 6th example.
But, this doesn't mean that you can't use verbs in your URIs, in fact there is a specific category called controller which as mentioned in the same guide:
A controller resource models a procedural concept. Controller resources are like executable functions, with parameters and return values; inputs and outputs.
Use “verb” to denote controller archetype.
This controllers resources could go well (I asume) with for example your
GET /tenant/:tenantId/users/activate/:username.
But I would think that the verb activate should go last:
GET /tenant/:tenantId/users/:username/activate
First note: REST doesn't care what spelling conventions you use for your resource identifiers. Once you figure out the right resources, you can choose any identifiers for them that you like (so long as those identifiers are consistent with the production rules defined in RFC 3986).
"Any information that can be named can be a resource" (Fielding, 2000), but its probably most useful to think about resources as abstractions of documents. We use HTTP as an application protocol whose application domain is the transfer of documents over a network.
GET
This is the method we use to retrieve a document
PATCH
PUT
POST
These methods all indicate requests to edit a document (specifically, to edit the request target).
PUT and PATCH are each ask the server to make its copy of a document look like the client's local copy. Imagine loading a web page into an editor, making changes, and then "saving" those changes back to the server.
POST is less specific; "here's a document that we created by filling in a web form, edit yourself appropriately". It is okay to use POST: after all, the web was catastrophically successful and we're still using POST in our form submissions.
The useful work is a side effect of these edits.
Are these RESTFul according to the REST principles?
Do they work like a web site? If they work like a web site: meaning you follow links, and send information to the server by submitting forms, or editing the webpages and submitting your changes to the server, then it is REST.
A trick though: it is normal in REST that a single method + request uri might have different useful side effects. We can have several different HTML forms that all share the same Form.action. Uploading changes to an order document might have very different effects if the edits are to the shipping address vs to the billing information or the order items.
Normal doesn't mean obligatory - if you prefer a resource model where each form request goes to a specific resource, that can be OK too. You get simpler semantics, but you support more resources, which can make caching trickier.
Is there a capability for or example of creating a Sparql HTTP endpoint with rdflib? We would want it to follow the spec and be able to return json and/or csv formats. This would mostly be for POC usage. It would also be possible to use Javascript/Node.
Thanks!
You might try https://github.com/rdflib/pyLDAPI. It's been touched much more recently than https://github.com/RDFLib/rdflib-web and there are some public examples of it to follow, e.g. https://geofabricld.net. Also, the SKOS-specific tool VocPrez uses it under the hood.
As of earlier this year, pyLDAPI implements the W3C's Content Negotiation by Profile specification which is, I suppose, the latest an greatest Linked Data API-relevant specification, although it's not just for Linked Data APIs.
Feel free to contact me directly if you need more of a hand with this.
I am creating API and trying to figure out is planned approach any good.
That API is not public and it will be used by SPA and mobile app that I build.So I am thinking of GraphQL-like design but without posting json and with regular HTTP methods.
Something like this for GET methods:
Example 1 - get users with specific fields(_join indicates sql table join), ordering and limit:api.com?table=users&displayFields=id,name,email,address,tel,country_join&orderBy=asc&orderColumn=name&offset=0&limit=10
Example 2 - get users based on search parameters with all fields, ordering and limit:api.com?table=users&search=John&searchFields=name,email&orderBy=asc&orderColumn=name&offset=0&limit=10
I assume this is bad since REST is standard, otherwise I would see much more examples of this approach.
But why is this bad? For me it seems easier to develop and more flexible to use.
Is proper REST API for examples I provided easier to implement, safer, easier to use or cache?
The main difference I see between putting the variables in the url vs the request body are:
the length of the data as the url length is limited while the request body is not
special characters to be escaped in the url which can lead to long and unclear url
These are 2 pros in favor of data in request body, but I agree that data in url is much simpler to test and use as tou don't need an http client tool like curl or postman to validate your endpoints.
REST however has stricter conventions if you want to fully implement it:
use the right http requests (get, post, patch, delete and put) to implement crud operations on one single endpoint
return the right http code as a result
use standard data format for input and output (json or XML)
For better interoperability between systems it's advised to comply with REST and microservices design patterns.
For small applications we can follow some shortcuts and not comply fully. I have integrated several services so far and each time I can tell you no one of them implements standard REST :-)
Lets consider the following flow to a RESTfull API:
API root
|
v
user list
|
v
user details
|
v
user messages
Suppose I have a client to consume the API, and I want to retrieve messages from a user with ID 42.
From what I've been studying, my client is not supposed to know how to "build" urls, and it should follow the links given by the API.
How should I do to retrieve messages for the user with ID 42?
The only way I can think is "walk" the whole API from it's root to user messages, which doesn't look very pretty or efficient to me.
Eg:
1 - GET / and get the link to the list of users
2 - GET /user/?id=42 and get the link to details of the user with the ID 42
3 - GET /user/42/ and get the link to user 42 list of messages
4 - GET /user/42/messages/ and finally get the user messages
Did I get something wrong? Is this the right way according to Roy's Fielding paper?
Or is it ok to just assume the messages url is "/user/{id}/messages/" and make the request directly?
Use URL templates in your API root. Let the client consume the API root at runtime. It should look for a URL template named something like "user-messages" with the value of "/user/{userid}/messages/". Then let the client substitute "42" for "{userid}" in the template and do a GET on the resulting URL. You can add as many of these URL templates you want for all of the required, often used, use cases.
The difference between this solution and a "classic" web API is the late binding of URLs: the client reads the API root with its templates at runtime - as opposed to compiling the client with the knowledge of the URL templates.
Take a look at the HAL media type for some information about URL templates: http://stateless.co/hal_specification.html
I wrote this piece here some time ago to explain the benefits of hypermedia: http://soabits.blogspot.dk/2013/12/selling-benefits-of-hypermedia.html
I believe what your real concern is should you go about implementing HATEOAS or not. Now as it's an integral part of REST specifications, it is recommended that each entity should have a link to it's child entity that it encompasses. In your case, API ROOT should show list of users with each "user" having a link (/root/users/{id}) to corresponding user's details. And each User details entity will contain a link to the list of "messages" (/root/users/{id}/messages) which, finally, inturn encompass the link to the actual message detail as well (/root/users/{id}/messages/{messageId}). This concept is extremely useful (and thus a part of the specifications) because the client doesn't need to know the url to where your entity is exposed. For example, if your users were on http://users.abc.com/rest/users/{id} but your messages were on http://messages.abc.com/rest/{userId}/messages/{messageId}, the user entity that encompasses the list of "messages" will already have link embedded to point to the right resource on a different server.
Now that being said, I haven't actually seen many REST implementations out there (I must admit I do not have TOO MUCH of an experience, but enough to give an opinion) where HATEOAS is being used widespread. In most cases the resources are almost always on the same server (environment) and the paths to resources are almost always relative to the root url.Thus, it doesn't make sense for the clients to parse out the embedded links from the object when they can generate one by themselves, especially when the client would like to provide access to a resource directly (View the message directly without getting the user entity provided you already know what the messageId is).
In the end, it all depends on how close do you want your REST implementations to that of specifications and what kind of clients are you going to have. My 2 cents would be: if you have time, implement REST with HATEOAS and feel proud about it :). There are libraries out there that will make this implementation (HATEOAS) somewhat transparent to you REST implementation (I believe spring has one, although not very mature. You can look at it here). If you are like me and don't have much time to go that route, I think you can continue with a normal REST implementation without HATEOAS and your clients will still be OK with it (or so I hope!)
Hope this helps!
I found this article about hacking urls: Avoid hackable URLs.
There is a very interesting discussion about the topic of this question in the comments section.
I'm building my first Rest API which serialize data to JSON and XML formats.
I would like to provide an index page to API clients, where they would be able to choose implemented endpoints.
What information do I need to include to make my API most useful, and how should I organize it?
That's a very complex question for a simple answer.
You may want to take a look at existing API frameworks, like Swagger Specification (OpenAPI), and services like apiary.io and apiblueprint.org.
Also, here's an example of the same REST API described, organized and even styled in three different ways. It may be a good start for you to learn from existing common ways.
https://api.coinsecure.in/v1
https://api.coinsecure.in/v1/originalUI
https://api.coinsecure.in/v1/slateUI#!/Blockchain_Tools/v1_bitcoin_search_txid
At the very top level I think quality REST API docs require at least the following:
a list of all your API endpoints (base/relative URLs)
corresponding HTTP GET/POST/... method type for each endpoint
request/response MIME-type (how to encode params and parse replies)
a sample request/response, including HTTP headers
type and format specified for all params, including those in the URL, body and headers
a brief text description and important notes
a short code snippet showing the use of the endpoint in popular web programming languages
Also there are a lot of JSON/XML-based doc frameworks which can parse your API definition or schema and generate a convenient set of docs for you. But the choice for a doc generation system depends on your project, language, development environment and many other things.