Python HAL generation/parsing library
Project description
halogen
Python HAL generation/parsing library.
Schemas can be defined to specify attributes to be exposed and a structure
Serialization
import halogen
spell = {
"uid": "abracadabra",
"name": "Abra Cadabra",
"cost": 10,
}
class Spell(halogen.Schema):
self = halogen.Link(URI("spells"), attr="uid")
name = halogen.Attr()
serialized = Spell.serialize(spell)This will produce HAL-like dictionary which can be serialized to json for the hal+json content type or to XML for the hal+xml content type.
{
"_links": {
"self": {"href": "spells/abracadabra"}
},
"name": "Abra Cadabra"
// The extra wasn't in the schema and this way will be ignored
}Embedded objects
import halogen
books = [
{
"id": "1",
"name": "Game of Thrones",
},
{
"id": "2",
"name": "Harry Potter",
}
]
class Book(halogen.Schema):
self = halogen.Link(URI("books"), attr="id")
name = halogen.Attr()
class BooksFeed(halogen.Schema):
self = halogen.Link(URI("books"), attr=lambda value: "/")
books = halogen.Embedded(halogen.types.List(Book))
feed = Spell.serialize(books)The serialized data will look like this:
{
"_links": {
"self": {"href": "/books/"}
},
"_embedded": {
"books": [
{
"_links": {
"self": {"href": "/books/1"}
},
"name": "Game of Thrones"
},
{
"_links": {
"self": {"href": "/books/2"}
},
"name": "Harry Potter"
}
]
}
}CURIEs
Curies can be declared in the global scope to be reused between schemas.
ACME = halogen.Curie(name="acme", href="/test/123")
data = {
"warehouse": "/test/123",
}
class Schema(halogen.Schema):
warehouse = halogen.Link(curie=ACME)
result = Schema.serialize(data)Curies used in links or embedded will be collected and placed in the _links.curies section.
{
_links: {
curies: [{
name: "acme",
href: "/test/123"
}],
"acme:warehouse": {href: /test/123}
}
}Constant types
Sometimes it is convenient to render constants for example in links. In this case you can simply specify the constant value instead of the attribute type.
class Schema(halogen.Schema):
self = halogen.Link("/test")Deserialization
The HAL data can be deserialized into the output object. In case there are validation errors they will be collected and the ValidationError thrown.
import halogen
hal = {
"_links": {
"self": {"href": "spells/abracadabra"}
},
"name": "Abra Cadabra",
}
class Spell(halogen.Schema):
self = halogen.Link(URI("spells"), attr="uid")
name = halogen.Attr()
spell = {}
Spell.deserialize(hal, output=spell)The deserialized data will look like this:
{
"uid": "abracadabra",
"name": "Abra Cadabra",
}Error handling
The errors will be related to the attributes.
try:
Spell.deserialize(hal, output=spell)
except halogen.ValidationError as e;
print e.as_dict()Changelog
0.0.3
Support curies
0.0.2
Deserialization implemented
Docstrings updated
0.0.1
Initial version
Release history Release notifications | RSS feed
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