openapi-path-templating
v1.6.0
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OpenAPI Path Templating parser, validator and resolver.
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openapi-path-templating
Path Templating allow defining values based on information that will only be available within the HTTP message in an actual API call. This mechanism is used by Paths Object of OpenAPI specification.
openapi-path-templating
is a parser, validator and resolver for OpenAPI Path Templating. It supports
Path Templating defined in following OpenAPI specification versions:
Table of Contents
Getting started
Installation
You can install openapi-path-templating
using npm
:
$ npm install openapi-path-templating
Usage
openapi-path-templating
currently supports parsing, validation and resolution.
Both parser and validator are based on a superset of ABNF (SABNF)
and use apg-lite parser generator.
Parsing
Parsing a Path Templating is as simple as importing the parse function and calling it.
import { parse } from 'openapi-path-templating';
const parseResult = parse('/pets/{petId}');
parseResult.result.success; // => true
parseResult variable has the following shape:
{
result: {
success: true,
state: 101,
stateName: 'MATCH',
length: 13,
matched: 13,
maxMatched: 13,
maxTreeDepth: 18,
nodeHits: 324
},
ast: fnast {
callbacks: [
'path-template': [Function: pathTemplate],
path: [Function: path],
query: [Function: query],
'query-marker': [Function: queryMarker],
fragment: [Function: fragment],
'fragment-marker': [Function: fragmentMarker],
slash: [Function: slash],
'path-literal': [Function: pathLiteral],
'template-expression': [Function: templateExpression],
'template-expression-param-name': [Function: templateExpressionParamName]
],
init: [Function (anonymous)],
ruleDefined: [Function (anonymous)],
udtDefined: [Function (anonymous)],
down: [Function (anonymous)],
up: [Function (anonymous)],
translate: [Function (anonymous)],
setLength: [Function (anonymous)],
getLength: [Function (anonymous)],
toXml: [Function (anonymous)]
}
}
Interpreting AST as list of entries
import { parse } from 'openapi-path-templating';
const parseResult = parse('/pets/{petId}');
const parts = [];
parseResult.ast.translate(parts);
After running the above code, parts variable has the following shape:
[
[ 'path-template', '/pets/{petId}' ],
[ 'path', '/pets/{petId}' ],
[ 'slash', '/' ],
[ 'path-literal', 'pets' ],
[ 'slash', '/' ],
[ 'template-expression', '{petId}' ],
[ 'template-expression-param-name', 'petId' ]
]
Interpreting AST as XML
import { parse } from 'openapi-path-templating';
const parseResult = parse('/pets/{petId}');
const xml = parseResult.ast.toXml();
After running the above code, xml variable has the following content:
<?xml version="1.0" encoding="utf-8"?>
<root nodes="7" characters="13">
<!-- input string -->
/pets/{petId}
<node name="path-template" index="0" length="13">
/pets/{petId}
<node name="path" index="0" length="13">
/pets/{petId}
<node name="slash" index="0" length="1">
/
</node><!-- name="slash" -->
<node name="path-literal" index="1" length="4">
pets
</node><!-- name="path-literal" -->
<node name="slash" index="5" length="1">
/
</node><!-- name="slash" -->
<node name="template-expression" index="6" length="7">
{petId}
<node name="template-expression-param-name" index="7" length="5">
petId
</node><!-- name="template-expression-param-name" -->
</node><!-- name="template-expression" -->
</node><!-- name="path" -->
</node><!-- name="path-template" -->
</root>
NOTE: AST can also be traversed in classical way using depth first traversal. For more information about this option please refer to apg-js and apg-js-examples.
Validation
Validating a Path Templating is as simple as importing the test function and calling it.
import { test } from 'openapi-path-templating';
test('/pets/{petId}'); // => true
test('/a{petId}'); // => true
test('/pets'); // => true
test('/pets', { strict: true }); // => false (doesn't contain any template-expression)
Resolution
Resolving a Path Templating is as simple as importing the resolve function and calling it.
import { resolve } from 'openapi-path-templating';
resolve('/pets/{petId}', { petId: 3 }); // => "/pets/3"
Resolved Path Templating is automatically encoded using encodeURIComponent function. It is possible to provide a custom encoder.
import { resolve } from 'openapi-path-templating';
resolve('/pets/{petId}', { petId: '/?#' }, {
encoder: (component) => component, // no encoding
}); // => "/pets//?#"
Grammar
New grammar instance can be created in following way:
import { Grammar } from 'openapi-path-templating';
const grammar = new Grammar();
To obtain original ABNF (SABNF) grammar as a string:
import { Grammar } from 'openapi-path-templating';
const grammar = new Grammar();
grammar.toString();
// or
String(grammar);
More about OpenAPI Path Templating
The Path Templating is defined by the following ABNF syntax
; OpenAPI Path Templating ABNF syntax
path-template = path [ query-marker query ] [ fragment-marker fragment ]
path = slash *( path-segment slash ) [ path-segment ]
path-segment = 1*( path-literal / template-expression )
query = *( query-literal )
query-literal = 1*( unreserved / pct-encoded / sub-delims / ":" / "@" / "/" / "?" / "&" / "=" )
query-marker = "?"
fragment = *( fragment-literal )
fragment-literal = 1*( unreserved / pct-encoded / sub-delims / ":" / "@" / "/" / "?" )
fragment-marker = "#"
slash = "/"
path-literal = 1*( unreserved / pct-encoded / sub-delims / ":" / "@" )
template-expression = "{" template-expression-param-name "}"
template-expression-param-name = 1*( unreserved / pct-encoded / sub-delims / ":" / "@" )
; Characters definitions (from RFC 3986)
unreserved = ALPHA / DIGIT / "-" / "." / "_" / "~"
pct-encoded = "%" HEXDIG HEXDIG
sub-delims = "!" / "$" / "&" / "'" / "(" / ")"
/ "*" / "+" / "," / ";" / "="
ALPHA = %x41-5A / %x61-7A ; A-Z / a-z
DIGIT = %x30-39 ; 0-9
HEXDIG = DIGIT / "A" / "B" / "C" / "D" / "E" / "F"
License
openapi-path-templating
is licensed under Apache 2.0 license.
openapi-path-templating
comes with an explicit NOTICE file
containing additional legal notices and information.