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:
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You can install openapi-path-templating using npm:
$ npm install openapi-path-templatingopenapi-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 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; // => trueparseResult 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)]
}
}
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' ]
]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.
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)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//?#"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);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"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.