dynamic_service

Description:

dynamic service

dynamic_service #


Table of Contents

Introduction
Steps

conditional
create_jwt
delay
etag
for_each
load_network
parallel
set_response
set_variables
shuffle_list
validate_jwt
validate_schema
write


Custom Steps
Types

Boolean Expression
Expression
JSON Expression
Step
Template
YAML Expression
YAON Expression





Introduction #
The Dynamic Service is a Dart based service that can have a dynamic API definition loaded from the local file system, a network URL, or any other custom plugin that supports loading data.
The package comes with an example client and an example server. The server has a Swagger definition to assist with describing the examples.

Steps #
The Dynamic Service operates by executing a series of Steps. Steps can be registered via the DynamicServiceRegistry.
conditional #
The conditional step will evaluate an Boolean Expression and determine what, if any, steps to execute next.
Type: conditional
Example:
- type: conditional
with:
condition: ${(claims['refresh'] ?? '').toString() == 'true'}
steps-false:
- type: set_response
with:
code: 401
content-type: text/plain
body: Not a valid refresh token
steps-true:
- type: set_response
with:
content-type: text/plain
body: Valid refresh token
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Parameters:



Name
Required
Type
Example
Description




condition
Yes
Boolean Expression
jwt.yaml
Expression that determines whether to execute the steps-true or steps-false steps next.


steps-false
No
Step[]
jwt.yaml
Zero or more steps to execute when the expression evaluates to false.


steps-true
No
Step[]
jwt.yaml
Zero or more steps to execute when the expression evaluates to true.




create_jwt #
The create_jwt step create a JWT with either a hs256 or rs256 based signature. The parameters
Type: create_jwt
Example:
- type: create_jwt
with:
accessToken:
expires: ${minutes(15).inSeconds}
key: ${key}
key-type: HS256
claims:
sub: ${body['username']}
refreshToken:
expires: ${days(14).inSeconds}
key: ${key}
key-type: HS256
claims:
refresh: true
sub: ${body['username']}
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Parameters:



Name
Required
Type
Example
Description




expires
No
[int]

Number of seconds


key
Yes
Boolean Expression
jwt.yaml
Expression that determines whether to execute the steps-true or steps-false steps next.


keyId | key-id
Yes
Step[]
jwt.yaml
Zero or more steps to execute when the expression evaluates to false.


keyType | key-type
Yes
Step[]
jwt.yaml
Zero or more steps to execute when the expression evaluates to false.




delay #

etag #

for_each #

load_network #

parallel #

set_response #

set_variables #

shuffle_list #

validate_jwt #

validate_schema #

write #

Custom Steps #
For example, to create a new step that can perform a custom action, you would update your main function to look like:
import 'package:dynamic_service/dynamic_service.dart';

Future<void> main(List<String> args) {
var registry = DynamicServiceRegistry.defaultInstance;
registry.registerStep(
type: _MyCustomStep.kType,
builder: (args) => _MyCustomStep(args: args),
);

await Server().start(args);
}

class _MyCustomStep extends ServiceStep {
_MyCustomStep({
Map<String, dynamic>? args,
}) : super(
args: args,
type: kType,
);
static const kType = 'my-custom-step';

@override
Future<void> applyStep(
ServiceContext context,
Map<String, dynamic> args,
) async {
// Your custom code goes here
}
}
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Types #
Boolean Expression #
An String Expression that evaluate to a true or false boolean result. The result is considered to be true when the final result from the expression resolves to one of:

true
yes
1

Examples:
${json_path(body, "$.name.first").isNotEmpty == true && json_path(body, "$.name.last").isNotEmpty == true}
${json_path(body, "$.name.first").isNotEmpty}
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Expression #
An String that uses the template_expressions syntax to evaluate a singular result.
Examples:
${json_path(body, "$.name.first").isNotEmpty == true && json_path(body, "$.name.last").isNotEmpty == true}
${json_path(body, "$.name.first").isNotEmpty}
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JSON Expression #
A JSON compatible List<String>, Map<String, dynamic> or JSON encoded string where the entries may each contain an Expression.
Examples:
{
"${json_path(body, \"$.name.first\")}": ".*\\S.*",
"${json_path(body, \"$.name.last\")}": ".*\\S.*"
}

[
"${json_path(body, \"$.name.first\").isNotEmpty}",
"${json_path(body, \"$.name.last\").isNotEmpty}"
]
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Step #

Template #
An string containing zero or more Expression's to create a String based result.
Examples:
"Howdy ${json_path(body, '$.name.first')} ${json_path(body, '$.name.last')}"
"Hello ${path['firstName']} ${path['lastName']}"
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YAML Expression #
A YAML compatible List<String>, Map<String, dynamic> or YAML encoded string where the entries may each contain an Expression.
Examples:
body:
'${json_path(body, "$.name.first")}': '.*\\S.*'
'${json_path(body, "$.name.last")}': '.*\\S.*'


body:
- '${json_path(body, "$.name.first").isNotEmpty}'
- '${json_path(body, "$.name.last").isNotEmpty}'

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YAON Expression #
Can be either a YAML Expression or a JSON Expression.