Struct Patch 

pub struct Patch<T> { /* private fields */ }

Available on crate feature transport only.

A partial update to an OCPI object.

Held as a JSON object rather than as a per-field Option struct, because that is what a merge patch is: the difference between “absent” and “present and null” is the whole semantics, and a struct of Options cannot express it.

use ocpi_kit::transport::Patch;
use ocpi_kit::v2_3_0::locations::Evse;

let patch: Patch<Evse> = serde_json::from_str(
    r#"{"status":"CHARGING","last_updated":"2019-06-24T12:39:09Z"}"#,
).unwrap();
assert!(patch.last_updated().is_some());
assert!(patch.touches("status"));

Spec: 2.3.0 §transport_and_format_patch

Implementations

impl<T> Patch<T>

pub fn from_value(body: Value) -> Self

Wraps a JSON value as a patch.

pub fn from_partial<P: Serialize>(value: &P) -> Result<Self, Error>

Builds a patch by serialising value, keeping only the fields it writes.

Errors

Propagates the serde_json error if value cannot be serialised.

pub const fn as_value(&self) -> &Value

The patch as a JSON value.

pub fn into_value(self) -> Value

Consumes the patch and yields the JSON value.

pub fn touches(&self, field: &str) -> bool

Whether the patch writes field at the top level, including writing it to null.

pub fn last_updated(&self) -> Option<DateTime>

The last_updated the patch carries, if any.

pub fn retype<U>(self) -> Patch<U>

Re-types this patch to the object it is meant to be applied to.

A merge patch is untyped on the wire, so a server extractor produces a Patch<serde_json::Value>; this names the type it will be applied to, which is what Patch::apply needs in order to check the result.

pub fn fields(&self) -> Vec<&str>

The fields the patch writes, at the top level.

impl<T> Patch<T>

where T: Serialize + DeserializeOwned + Validate,

pub fn apply(&self, target: &T) -> Result<T, OcpiError>

Applies this patch to target, returning the updated object.

The whole operation is checked before anything is returned:

• a patch without last_updated is refused with 2001, as the spec’s own example says;
• the merged object must still deserialise into T, so a patch that removes a required field is refused rather than producing a half-object;
• the merged object must still satisfy Validate, so a patch cannot turn a conformant object into a non-conformant one.

Errors

Returns OcpiError::Decode with a 2001-shaped message when any of those fail.

Trait Implementations

impl<T: Clone> Clone for Patch<T>

fn clone(&self) -> Patch<T>

Returns a duplicate of the value.

fn clone_from(&mut self, source: &Self)

Performs copy-assignment from source.

impl<T: Debug> Debug for Patch<T>

fn fmt(&self, f: &mut Formatter<'_>) -> Result

Formats the value using the given formatter.

impl<'de, T> Deserialize<'de> for Patch<T>

fn deserialize<__D>(__deserializer: __D) -> Result<Self, __D::Error>

where __D: Deserializer<'de>,

Deserialize this value from the given Serde deserializer.

impl<T> Display for Patch<T>

fn fmt(&self, f: &mut Formatter<'_>) -> Result

Formats the value using the given formatter.

impl<T: PartialEq> PartialEq for Patch<T>

fn eq(&self, other: &Patch<T>) -> bool

Equality operator ==.

fn ne(&self, other: &Rhs) -> bool

Inequality operator !=.

impl<T> Serialize for Patch<T>

fn serialize<__S>(&self, __serializer: __S) -> Result<__S::Ok, __S::Error>

where __S: Serializer,

Serialize this value into the given Serde serializer.

impl<T: PartialEq> StructuralPartialEq for Patch<T>