Struct tera::Context

pub struct Context<S: ContextSafety> { /* fields omitted */ }

The struct that holds the context of a template rendering.

Light wrapper around a BTreeMap for easier insertions of Serializable values

ContextSafety will be defined at creation time as either CtxThreadSafe or CtxThreadLocal, deciding what values Context-local functions may capture.

Implementations

impl Context<CtxThreadSafe>

pub fn new() -> Self

Initializes an empty context that is Send and Sync and can have functions capturing only Send and Sync values.

pub fn from_value(obj: Value) -> TeraResult<Self>

Takes a serde-json Value and convert it into a Context with no overhead/cloning.

pub fn from_serialize(value: impl Serialize) -> TeraResult<Self>

Takes something that impl Serialize and create a context with it. Meant to be used if you have a hashmap or a struct and don’t want to insert values one by one in the context.

pub fn register_function<T: Function + 'static, S: Into<String>>(
    &mut self,
    key: S,
    val: T
)

Registers Context-local function

impl Context<CtxThreadLocal>

pub fn new_threadlocal() -> Self

Initializes an empty context that is neither Send nor Sync but can have functions capturing non-Send and non-Sync values.

pub fn register_function<T: FunctionRelaxed + 'static, S: Into<String>>(
    &mut self,
    key: S,
    val: T
)

Registers Context-local function

impl<S: ContextSafety> Context<S>

pub fn insert<T: Serialize + ?Sized, S1: Into<String>>(
    &mut self,
    key: S1,
    val: &T
)

Converts the val parameter to Value and insert it into the context.

Panics if the serialization fails.

let mut context = tera::Context::new();
context.insert("number_users", &42);

pub fn try_insert<T: Serialize + ?Sized, S1: Into<String>>(
    &mut self,
    key: S1,
    val: &T
) -> TeraResult<()>

Converts the val parameter to Value and insert it into the context.

Returns an error if the serialization fails.

let mut context = Context::new();
// user is an instance of a struct implementing `Serialize`
if let Err(_) = context.try_insert("number_users", &user) {
    // Serialization failed
}

pub fn extend<S2: ContextSafety>(&mut self, source: Context<S2>)

Appends the data of the source parameter to self, overwriting existing keys. The source context will be dropped.

let mut target = Context::new();
target.insert("a", &1);
target.insert("b", &2);
let mut source = Context::new();
source.insert("b", &3);
source.insert("d", &4);
target.extend(source);

pub fn into_json(self) -> Value

Converts the context to a serde_json::Value consuming the context.

pub fn get(&self, index: &str) -> Option<&Value>

Returns the value at a given key index.

pub fn remove(&mut self, index: &str) -> Option<Value>

Remove a key from the context, returning the value at the key if the key was previously inserted into the context.

pub fn contains_key(&self, index: &str) -> bool

Checks if a value exists at a specific index.

pub fn get_function(&self, fn_name: &str) -> Option<&S>

Looks up Context-local registered function

Trait Implementations

impl<S: Clone + ContextSafety> Clone for Context<S>

fn clone(&self) -> Context<S>

Returns a copy of the value.

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

Performs copy-assignment from source.

impl<S: ContextSafety> Debug for Context<S>

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

Formats the value using the given formatter.

impl Default for Context<CtxThreadSafe>

fn default() -> Context<CtxThreadSafe>

Returns the “default value” for a type.

impl<S: ContextSafety> PartialEq<Context<S>> for Context<S>

fn eq(&self, other: &Self) -> bool

This method tests for self and other values to be equal, and is used by ==.

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

This method tests for !=.