Fields¶
Guillotina uses schemas to define content types and behaviors. These schemas consist of field definitions.
Available fields¶
- guillotina.schema.Bool
- guillotina.schema.Bytes
- guillotina.schema.Choice: validates against vocabulary of values
- guillotina.schema.Date
- guillotina.schema.Datetime
- guillotina.schema.Decimal
- guillotina.schema.Dict
- guillotina.schema.Float
- guillotina.schema.Int
- guillotina.schema.JSONField
- guillotina.schema.List
- guillotina.schema.Set
- guillotina.schema.Text
- guillotina.schema.TextLine
- guillotina.schema.Time
- guillotina.fields.PatchField: allow updating value without patching entire value
- guillotina.fields.BucketListField: optimized storage for very large lists of data
- guillotina.fields.BucketDictField: optimized storage for very large dictionaries of data
- guillotina.files.CloudFileField: file field for storing in db or cloud storage
Default values¶
All the fields listed above can be configured to use a value as fallback when a value it’s not provided. There are two ways to define it:
- Using the argument
missing_value
we can define the value we want to set to the field. For example, a schema with the fieldcounter = schema.Int(missing_value=0)
will be set to0
during creation if no value is provided for the keycounter
. - Using the argument
default
(ordefaultFactory
) we achive a similar behavior with one difference: the default value it’s not stored in the object (this means that internally, the object isNone
) until a value it’s provided explicitly.
Patch field¶
Guillotina provides a PatchField
which allows you to patch values of
List
, Dict
and Int
fields without having the original value.
This is done doing a PATCH request to the object absolute url with
the following payloads:
Patch field list¶
from zope.interface import Interface
from guillotina.fields import PatchField
from guillotina import schema
class IMySchema(Interface):
field = PatchField(schema.List(
value_type=schema.Text()
))
Then, payload for patching to append to this list would look like:
{
"field": {
"op": "append",
"value": "foobar"
}
}
Append if unique value only:
{
"field": {
"op": "appendunique",
"value": "foobar"
}
}
Extend:
{
"field": {
"op": "extend",
"value": ["foo", "bar"]
}
}
Extend if unique values:
{
"field": {
"op": "extendunique",
"value": ["foo", "bar"]
}
}
Delete:
{
"field": {
"op": "del",
"value": 0
}
}
Remove:
{
"field": {
"op": "remove",
"value": "foobar"
}
}
Update:
{
"field": {
"op": "update",
"value": {
"index": 0,
"value": "Something new"
}
}
}
Clear:
{
"field": {
"op": "clear"
}
}
Multiple operations:
{
"field": {
"op": "multi",
"value": [
{
"op": "del",
"value": 0
},
{
"op": "append",
"value": "foobar"
}
]
}
}
Patch dict field¶
from zope.interface import Interface
from guillotina.fields import PatchField
from guillotina import schema
class IMySchema(Interface):
field = PatchField(schema.Dict(
key_type=schema.Text(),
value_type=schema.Text()
))
Then, payload for patching to add to this dict would look like:
{
"field": {
"op": "assign",
"value": {
"key": "foo",
"value": "bar"
}
}
}
Delete:
{
"field": {
"op": "del",
"value": "foo"
}
}
Update:
{
"field": {
"op": "update",
"value": [{
"key": "foo",
"value": "bar"
}, {
"key": "foo2",
"value": "bar2"
}]
}
}
Clear:
{
"field": {
"op": "clear"
}
}
Multiple operations:
{
"field": {
"op": "multi",
"value": [
{
"op": "del",
"value": "foo"
},
{
"op": "assign",
"value": {
"key": "foo3",
"value": "bar3"
}
}
]
}
}
Patch int field¶
PatchField
can also be used on Int
fields to increment, decrement
or reset their original value.
from zope.interface import Interface
from guillotina.fields import PatchField
from guillotina import schema
class IMySchema(Interface):
counter = PatchField(schema.Int(
title='My Counter',
default=1,
))
The payload to increment counter
by 3 units would look like:
{
"counter": {
"op": "inc",
"value": 3
}
}
Notice that, at this point, counter
will be set to 4 because its
default value is 1. If the default would not be set, the increment
operation assumes a 0, and thus counter
would be 3.
Likewise, to decrement the field, the following payload would work:
{
"counter": {
"op": "dec",
"value": 4
}
}
To reset counter
to its default value, you can send the following
payload without value
:
{
"counter": {
"op": "reset"
}
}
and counter
will be set to its default value 1. Otherwise, you can
also send the target reset value:
{
"counter": {
"op": "reset",
"value": 0
}
}
Notice that a reset operation on a integer without a default value is equivalent to sending a value of 0.
Bucket list field¶
from zope.interface import Interface
from guillotina.fields import BucketListField
from guillotina import schema
class IMySchema(Interface):
field = BucketListField(
value_type=schema.Text(),
bucket_len=5000
)
Then, payload for patching to append to this list would look like:
{
"field": {
"op": "append",
"value": "foobar"
}
}
Extend:
{
"field": {
"op": "extend",
"value": ["foo", "bar"]
}
}
Delete:
{
"field": {
"op": "del",
"value": {
"bucket_index": 0,
"item_index": 0
}
}
}
Clear:
{
"field": {
"op": "clear"
}
}
Bucket dict field¶
from zope.interface import Interface
from guillotina.fields import BucketDictField
from guillotina import schema
class IMySchema(Interface):
field = BucketDictField(
key_type=schema.Text(),
value_type=schema.Text(),
bucket_len=5000
)
Then, payload for patching would be…:
{
"field": {
"op": "assign",
"value": {
"key": "foo",
"value": "bar"
}
}
}
Update:
{
"field": {
"op": "update",
"value": [{
"key": "foo",
"value": "barupdated"
}, {
"key": "other",
"value": "othervalue"
}]
}
}
Delete:
{
"field": {
"op": "del",
"value": "foo"
}
}
Clear:
{
"field": {
"op": "clear"
}
}
Field validation¶
constraints¶
To provide additional field validation, you can provide a constraint for a field.
This is a simple callable that takes an argument with the value that is being validated for the field.
The most simple type of constraint is to use a lambda function:
from zope.interface import Interface
from guillotina import schema
class IMySchema(Interface):
field = schema.Text(constraint=lambda val: val != 'foobar')
field validators¶
To provide more complex field validation, you can use the validator
field decorator:
from zope.interface import Interface
from guillotina import schema
class IMySchema(Interface):
field = schema.Text()
@field.validator
def validate_field(field, value):
# field is bound field so we can look at context now
return field.context.foobar is None
invariants¶
You can also validate the modified objects with invariants.
from zope.interface import Interface, invariant, Invalid
from guillotina import schema
class IMySchema(Interface):
field = schema.Text()
@invariant
def validate_obj(obj):
# field is bound field so we can look at context here
if obj.foo is None and obj.bar is None:
raise Invalid(obj)