README

Index:

Intro
Routes
- Root Route
Install
Setup
- Configurations
- Resources list
Usage
HTTP Methods
Query parameters
Cache
Authentication and Authorization
Errors
Extending
Changelog

Intro

A Router framework to bootstrap RESTful APIs based on Medools.

Routes

Basically, all routes are formatted as:

/resource: Requests a collection of resources
/resource/id: Requests a specific resource

See bellow details about the resource name.

The resource id depends on the PRIMARY_KEY defined in the model. Usually it is an integer, but if there is a composite PRIMARY_KEY, each column must be in the id, separated by primary_key_separator, e.g. /resource/1-1.

Also, resources can be nested:

/resource/id/resource_1: Requests a collection of resource_1 with resource(id) in the appropriate foreign column*
/resource/id/resource_1/offset: Requests a specific resource from the collection in the previous topic. offset works as collection[offset - 1], i.e. it is not resource_1's id, and has 1-based index

Nesting is only allowed in resources (not in collections: /resource/resource_1 is wrong), but the route can end in a collection. And there is no hard limit of nesting levels, the only requirement is that the last resource (or collection) has a foreign key to the previous resource, that has a foreign key to the previous one, and so on. The id is only used in the first resource.

* If resource_1 has multiple foreign columns for resource, only the first one is used. As a work around, you can use Collection query parameters to filter the correct column

Root Route

When requesting the / route, a count of all resources is returned. If the meta config is not empty, it is also included. An OPTIONS request just lists all implemented methods.

Install

Open a terminal in your project directory and run:

composer require aryelgois/medools-router

Setup

Medools requires a config file to connect to your database. (see more here)

Additionally, you will need some configurations and a resources list for your API.

Also, if using authentication, you will need a secret file (or multiple files) and a Sign up system (or an administrator will add valid credentials).

Configurations

The Router accepts an array of configurations that will be passed to properties in it. The array may contain:

always_cache (boolean): If GET and HEAD requests always check cache headers (default: true)
always_expand (boolean): If foreign models are always expanded in a GET resource request (default: false)
authentication (mixed[]|null): Specify how to authenticate the requests. If null, the authentication is disabled. If set, can contain the keys:
- secret (string) required: Path to secret used to sign the JWT tokens. It can be a file or a directory
  
  If it is a directory, the Router expects it to contain secrets named after their expiration time, in a unix timestamp. Only the first file is used, and the tokens expire at maximum in the same stamp as the secret. You can use a cron job to keep generating more secrets
  
  DO NOT keep the secret in your web server's public directory, neither let git track it
- realm (string): Sent in WWW-Authenticate Header
- algorithm (string): Hash algorithm used to sign the tokens (default: HS256)
- claims (mixed[]): Static JWT claims to be included in every token. Some claims are already defined by the Router: iss, iat, exp and user
- expiration (int): Expiration duration (in seconds) used to calculate the exp claim. It is limited by the secret timestamp (when secret is a directory)
- verify (boolean): If the authentication's email must be verified (default: false)
cache_method (string): Function used to hash the Response Body, for HTTP caching GET and HEAD requests. It receives a string with the body serialized (default: md5)
default_content_type (mixed[]): Default content type for GET requests. It is combined with resource's GET handlers

The default is application/json with internal handlers
default_filters (string|string[]|null): Default value for resources' filters. See more in Resources list filters option
default_publicity (boolean|string[]|string): Default value for resources' public option
- false: All resources are private by default. It only has effect if authentication is not null
- true: All resources are public by default. It has the same effect as not defining authentication, but if it is defined, this value is useful to make most resources public and some private
- string[]: List of methods that are always public
- string: The same as an array with one item
extensions (string[]): Map of file extensions and a related content type

It allows overriding browser's Accept header with an extension in the URL. Fill it with extensions for custom content types your resources use

Note that it is only checked by safe methods and is only useful to resources that define custom GET handlers. Using unknown extensions or when they are not expected may invalidate the route
implemented_methods (string[]): List of HTTP methods implemented by the API. You can limit which methods can be used, but to add more methods you would need to extend or modify the Router class
meta (mixed[]|null): Contains information to be included in the response for the root route. You can use it to add links to your project or documentation
per_page (integer): Limit how many resources can be returned in a collection request. If 0, no pagination is done (default: 20)
primary_key_separator (string): Separator used in composite PRIMARY_KEY (default: -)

It does not need to be a single character, since it is used as explode delimiter. But it must not be contained in the id itself, and can not contain forward slash /
zlib_compression (boolean): If should enable zlib compression when appropriate (default: true)

Resources list

A map of resource names to Medools Models, and optionally to specific configurations for that resource.

The resource names should be plural. You should choose the casing convention to be camelCase or snake_case. Prefer keeping consistent with the columns casing in your models.

The value mapped can be either a string with the Fully Qualified Model Class, or an array with:

model (string) required: Fully Qualified Model Class
methods (string|string[]): Allowed HTTP methods. Defaults to implemented_methods. OPTIONS is implicitly included
handlers (mixed[]): Map of HTTP methods to php functions that process the Request
- Several levels of arrays are allowed but not required, in the order: HTTP method => Content type => Resource kind (resource or collection). The leaves must be the function names
- These functions receive a Resource and must be capable of generating all the output (both Headers and Body) for the Response. Exceptions are catched by the Router
- The same handlers for GET are used for HEAD requests, and a HEAD key is ignored. Content types for GET are related to the accepted Response, while other methods use them with the Request's payload
- GET content types enable their related extensions in the route endpoint
- All methods implicitly have an internal application/json handler. If a method defines a single handler (i.e. a string) or if a application/json key is set, the internal handler is disabled for that method (unless using the magic value __DEFAULT__)
- When defining a single Resource kind (or setting one to null), requesting the disabled one is not acceptable
filters (string|string[]): List of columns that can be used as query parameters to filter collection requests. It also accepts a string of a special fields group (see fields query parameter), or ALL to allow filtering on any column. It replaces the default_filters config
cache (boolean): If caching headers should be sent. It overrides the always_cache config
max_age (int): Cache-Control max-age (seconds). Tells how long the cache is considered fresh until it becomes stale and the client needs to validate with a request to the server
public (boolean|string[]|string): Behaves like default_publicity, and is only used if authentication config is set

Usage

Follow the example to see how to use this framework in your web server.

When a request is done, your web server must redirect to a php script. If you are using Apache, there is already a .htaccess in the example that does the job.

First, the script requires Composer's autoloader and loads Medools config. Then it gathers request data:

Method: A HTTP method
URI: Requested route. It must not contain the path to the api directory, but query parameters must remain in the URI
Headers: Headers in the request. Used headers are:
- Authorization: Contains credentials for authenticating the request. Possible types are Basic and Bearer
- X-HTTP-Method-Override: If your clients can not work with PUT, PATCH or DELETE, they can use it to replace POST method. It is enabled by ENABLE_METHOD_OVERRIDE
- Content-Type: Data in the request payload is expected to be application/json by default. Resources may specify more types they read with external handlers
- Accept: The Router responses are, by default, in application/json. But resources may define more types they output, associated to external handlers
- If-None-Match: If caching headers are enabled, it is checked to see if a stale cache can still be used
Body: Raw data from the payload that will be parsed
URL: URL that access the Router. It is used to create links to other resources

Finally, a Router object is created with a resources list, optional configurations and all that data from the request. It will do its best to solve the route and give a response.

The resources list and configurations can be stored in a external file, like .json or .yml or something else. Remember to add a library to parse that file before passing to the Router.

You can also configure a subdomain like api.example.com to handle the routes. It is up to you.

SECURITY NOTE: It is highly recommended that you use SSL to protect your data transactions

HTTP Methods

The following HTTP methods are implemented by the Router class:

GET: By default, responses contain a JSON representation of the requested route
- Resource requests include a Link header listing the location of foreign models
- Collection requests include a Link header for pagination and a X-Total-Count counting all resources (ignoring pagination, but considering filters), unless per_page is 0
- Also, caching headers are sent, if enabled
Different content types can be configured per resource and it is chosen based on request's Accept header. They will not send the headers listed previously (unless the external handler sends by itself)
HEAD: Does the same processing for GET, but only send headers (even for external handlers)
OPTIONS: Lists allowed methods for the requested route in Allow header. It is a special method that is always allowed, if implemented
POST: Creates a new resource inside the collection with data in the request payload. A route to the new resource is in Location header. This method is not allowed for resource routes
PATCH: Sets one or more columns to a specific value, then responses with a GET of the current state
PUT: Replaces the requested resource with data in the request payload (all required columns must be passed), or create a new one if it does not exist. The response is a GET of the current state. This method is not allowed for collection routes

The PRIMARY_KEY columns can be omitted if they are in the route, i.e. a route without nested resources. In this case, the same columns in the payload have preference over the route
DELETE: Removes the resource or collection's resources from the Database

Some notes:

Pagination is disabled by default for a collection PATCH or DELETE, but the client can explicitly use it with page or per_page query parameters
A Content-Location Header can be sent, implying an updated or better route to the requested entity

Query parameters

The client can use some query parameters for a more precise request:

Collection request

sort: List of comma separated columns to be sorted. A possible unary negative implies descending sort order

Example: ?sort=-priority,stamp sorts in descending order of priority. Within a specific priority, older entries are ordered first
page: Collection page the client wants to access. It has 1-based index
per_page: An integer limiting how many entries should be returned. It overrides per_page config. As syntax sugar, all is the same as 0
filters: Defined in resources list, allows a fine control of the collection. Additional operators can make advanced filters:

Operator	Medoo counterpart	Name
gt	>	Greater Than
ge	>=	Greater or Equal to
lt	<	Lesser Than
le	<=	Lesser or Equal to
ne	!	Not Equal
bw	<>	BetWeen
nw	><	Not betWeen
lk	~	LiKe
nk	!~	Not liKe
rx	REGEXP	RegeXp

Examples:

A simple string represents a list of comma separated values:

?id=1,2,3 → ['id' => ['1', '2', '3']]
A numeric array can also be used:

?filter[]=1&filter[]=2&filter[]=foo,bar → ['filter' => ['1', '2', 'foo,bar']]

Helps including a comma in the item itself
bw and nw accept two values separated by comma. ne, lk and nk accept one or more values separated in the same way:

?id[bw]=100,200 → ['id[<>]' => ['100', '200']]
They also accept their multiple values in an array:

?filter[ne][]=1&filter[ne][]=2&filter[ne][]=foo,bar → ['filter[!]' => ['1', '2', 'foo,bar']]
Passing NULL to ne or directly to the filter will work:

?active=NULL → ['active' => null]

?active[ne]=NULL → ['active[!]' => null]

Notes:

Filters must be enabled by default_filters or in resource's filters
Filters affect the pagination and the X-Total-Count Header
Avoid columns with the same name as other query parameters

Resource request

expand: Its existence forces foreign models to be expanded, unless its value is false, which is useful if always_expand is true

Collection or Resource

fields: List of comma separated columns to include in the response. It also limits which foreign models are listed in Link Header, if not expanding them

There are special fields group that are replaced by the corresponding resource columns. They have the same names as the Medools constants:
- PRIMARY_KEY
- AUTO_INCREMENT
- STAMP_COLUMNS
- OPTIONAL_COLUMNS
- FOREIGN_KEYS
- SOFT_DELETE
Notes:
- Omitting or giving an empty fields parameter results in all fields in the response. But passing a query that solves to nothing (like ?fields=FOREIGN_KEYS in a resource without foreigns, or simply ?fields=,) results in no fields being sent
- It does not affect the order the fields are sent (also, in JSON objects are unordered) and repeated fields (maybe because of the groups) are ok

Cache

If enabled, caching headers ETag and Cache-Control are sent with successful responses that have a body.

This functionality can be enabled globally or per resource.

If the client sends If-None-Match Header, it is tested to provide a 304 Not Modified response.

Authentication and Authorization

By default, all resources are public. Defining the authentication config makes all resources private and to access them the client must authenticate. In this case, some resources may define themselves as public, or allow a few methods for unauthenticated requests.

To authenticate, first the client must provide some credentials to the Router with a Basic Authorization Header. In the example, it is at the /auth route. If authenticated, the server sends back a JWT token. This token must be sent to all the other routes with a Bearer Authorization Header until it expires. When it happens, the client must authenticate again.

Authentication credentials ("Accounts") are stored in the authentications table, with the columns:

id: Unique id sent in the token
username: Because of HTTP Basic Authentication limitations, it must not contain the colon character (:)
password: Contains an encrypted representation of the account's password
email: For contacting the account user
verified: Tells if the email was verified
enabled: Useful to block an account but keep its data
update and stamp: Just some timestamps

Another table, authorizations, maps accounts to authorized resources. It can also list authorized methods and can include a filter passed directly to Medoo, to limit which entries are authorized.

These two tables are be filled by your Sign up system, and controlled by an user panel or an administrator.

Errors

When possible, the Router will return an error response with an appropriate HTTP Status code and a JSON payload with code and message keys. Other keys may appear, but are optional.

Error table:

Code	Name	Status	Description
0	`ERROR_UNKNOWN_ERROR`	500	Unknown error placeholder
1	`ERROR_INTERNAL_SERVER`	500	The Router detected a Server error
2	`ERROR_INVALID_CREDENTIALS`	401	Authorization Header is invalid
3	`ERROR_UNAUTHENTICATED`	401	Request could not be authenticated
4	`ERROR_INVALID_TOKEN`	401	Authorization token is invalid
5	`ERROR_METHOD_NOT_IMPLEMENTED`	501	Requested Method is not implemented in the Router
6	`ERROR_UNAUTHORIZED`	403	Requested resource is not public and the client does not have authorization to access it
7	`ERROR_INVALID_RESOURCE`	400	Route contains invalid resource
8	`ERROR_INVALID_RESOURCE_ID`	400	Route contains invalid resource id
9	`ERROR_INVALID_RESOURCE_OFFSET`	400	Route contains invalid resource offset
10	`ERROR_INVALID_RESOURCE_FOREIGN`	400	Nested resource does not have foreign key to previous resource
11	`ERROR_RESOURCE_NOT_FOUND`	404	Requested resource does not exist in the Database
12	`ERROR_UNSUPPORTED_MEDIA_TYPE`	415	Request's Content-Type is not supported
13	`ERROR_INVALID_PAYLOAD`	400	Request's Content-Type has syntax error or is invalid
14	`ERROR_METHOD_NOT_ALLOWED`	405	Requested Method is not allowed for Route
15	`ERROR_NOT_ACCEPTABLE`	406	Requested resource can not generate content complying to Accept header
16	`ERROR_INVALID_QUERY_PARAMETER`	400	Query parameter has invalid data
17	`ERROR_UNKNOWN_FIELDS`	400	Resource does not have requested fields
18	`ERROR_READONLY_RESOURCE`	400	Resource can not be modified
19	`ERROR_FOREIGN_CONSTRAINT`	400	Foreign constraint fails

If an error or exception was not handled correctly, the response body is unpredictable and may depend on error_reporting.

Extending

You can extend the Router class to hack its code. Just remember to pass the correct class to the Controller.

aryelgois / medools-router

Maintainers

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