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/*!
A crate to help build DynamoDB condition, filter, key condition, and update
expressions in a type-safe way, including using [expression attribute names][1]
and [expression attribute values][2].
[`Path`] represents a [DynamoDB document path][3], and has many methods for
building various expressions. [`Expression`] is the type to use for a [DynamoDB
expression][4].
An example showing a how to use this crate to perform a query:
```no_run
# async fn example_query() -> Result<(), Box<dyn std::error::Error + Send + Sync>> {
use aws_config::BehaviorVersion;
use aws_sdk_dynamodb::Client;
use dynamodb_expression::{Expression, Num, Path};
let client = Client::new(&aws_config::load_defaults(BehaviorVersion::latest()).await);
let query_output = Expression::builder()
.with_filter(
"name"
.parse::<Path>()?
.attribute_exists()
.and("age".parse::<Path>()?.greater_than_or_equal(Num::new(2.5))),
)
.with_projection(["name", "age"])
.with_key_condition("id".parse::<Path>()?.key().equal(Num::new(42)))
.build()
.query(&client)
.table_name("people")
.send()
.await?;
#
# _ = query_output;
# Ok(())
# }
```
From here, see [`Path`] for building updates, filters, or conditions, and then
[`Expression`] to turn those into DynamoDB expressions.
# What about Rusoto?
[Rusoto][5] is intentionally not supported.
If you are using Rusoto and want to take advantage of this crate, you can still
build an [`Expression`], then convert the [`aws_sdk_dynamodb::types::AttributeValue`]
that are in the `expression_attribute_values` field into [`rusoto_dynamodb::AttributeValue`].
The rest of the fields are already what's needed.
```no_run
# async fn example_rusoto() -> Result<(), Box<dyn std::error::Error + Send + Sync>> {
use aws_sdk_dynamodb::{primitives::Blob, types::AttributeValue as AwsAv};
use dynamodb_expression::{Expression, Num, Path};
use itermap::IterMap;
use rusoto_core::Region;
use rusoto_dynamodb::{AttributeValue as RusotoAv, DynamoDb, DynamoDbClient, QueryInput};
let expression = Expression::builder()
.with_filter(
"name"
.parse::<Path>()?
.attribute_exists()
.and("age".parse::<Path>()?.greater_than_or_equal(Num::new(2.5))),
)
.with_projection(["name", "age"])
.with_key_condition("id".parse::<Path>()?.key().equal(Num::new(42)))
.build();
let input = QueryInput {
filter_expression: expression.filter_expression,
projection_expression: expression.projection_expression,
key_condition_expression: expression.key_condition_expression,
expression_attribute_names: expression.expression_attribute_names,
expression_attribute_values: expression
.expression_attribute_values
.map(|values| values.into_iter().map_values(convert_av).collect()),
table_name: String::from("people"),
..QueryInput::default()
};
let output = DynamoDbClient::new(Region::UsEast1).query(input).await?;
fn convert_av(av: AwsAv) -> RusotoAv {
let mut rav = RusotoAv::default();
match av {
AwsAv::B(av) => rav.b = Some(av.into_inner().into()),
AwsAv::Bool(av) => rav.bool = av.into(),
AwsAv::Bs(av) => {
rav.bs = Some(
av.into_iter()
.map(Blob::into_inner)
.map(Into::into)
.collect(),
)
}
AwsAv::L(av) => rav.l = Some(av.into_iter().map(convert_av).collect()),
AwsAv::M(av) => rav.m = Some(av.into_iter().map_values(convert_av).collect()),
AwsAv::N(av) => rav.n = av.into(),
AwsAv::Ns(av) => rav.ns = av.into(),
AwsAv::Null(av) => rav.null = av.into(),
AwsAv::S(av) => rav.s = av.into(),
AwsAv::Ss(av) => rav.ss = av.into(),
_ => unimplemented!(
"A variant was added to aws_sdk_dynamodb::types::AttributeValue \
and not implemented here: {av:?}",
),
}
rav
}
#
# _ = output;
# Ok(())
# }
```
[1]: https://docs.aws.amazon.com/amazondynamodb/latest/developerguide/Expressions.ExpressionAttributeNames.html
[2]: https://docs.aws.amazon.com/amazondynamodb/latest/developerguide/Expressions.ExpressionAttributeValues.html
[3]: https://docs.aws.amazon.com/amazondynamodb/latest/developerguide/Expressions.Attributes.html#Expressions.Attributes.NestedElements.DocumentPathExamples
[4]: https://docs.aws.amazon.com/amazondynamodb/latest/developerguide/Expressions.html
[5]: https://docs.rs/rusoto_dynamodb/
[`rusoto_dynamodb::AttributeValue`]: https://docs.rs/rusoto_dynamodb/latest/rusoto_dynamodb/struct.AttributeValue.html
*/
// Re-export the crates publicly exposed in our API
pub use ::aws_sdk_dynamodb;
pub use ::num;
pub mod condition;
mod expression;
pub mod key;
pub mod operand;
pub mod path;
pub mod update;
pub mod value;
pub use expression::{Builder, Expression};
pub use path::Path;
pub use value::{Map, Num, Scalar, Set, Value};
/// This exists just for formatting the doc examples.
#[cfg(test)]
mod examples {
#[allow(dead_code)]
async fn example_query() -> Result<(), Box<dyn std::error::Error + Send + Sync>> {
use crate::{Expression, Num, Path};
use aws_config::BehaviorVersion;
use aws_sdk_dynamodb::Client;
let client = Client::new(&aws_config::load_defaults(BehaviorVersion::latest()).await);
let query_output = Expression::builder()
.with_filter(
"name"
.parse::<Path>()?
.attribute_exists()
.and("age".parse::<Path>()?.greater_than_or_equal(Num::new(2.5))),
)
.with_projection(["name", "age"])
.with_key_condition("id".parse::<Path>()?.key().equal(Num::new(42)))
.build()
.query(&client)
.table_name("people")
.send()
.await?;
_ = query_output;
Ok(())
}
#[allow(dead_code)]
async fn example_rusoto() -> Result<(), Box<dyn std::error::Error + Send + Sync>> {
use crate::{Expression, Num, Path};
use aws_sdk_dynamodb::{primitives::Blob, types::AttributeValue as AwsAv};
use itermap::IterMap;
use rusoto_core::Region;
use rusoto_dynamodb::{AttributeValue as RusotoAv, DynamoDb, DynamoDbClient, QueryInput};
let expression = Expression::builder()
.with_filter(
"name"
.parse::<Path>()?
.attribute_exists()
.and("age".parse::<Path>()?.greater_than_or_equal(Num::new(2.5))),
)
.with_projection(["name", "age"])
.with_key_condition("id".parse::<Path>()?.key().equal(Num::new(42)))
.build();
let input = QueryInput {
filter_expression: expression.filter_expression,
projection_expression: expression.projection_expression,
key_condition_expression: expression.key_condition_expression,
expression_attribute_names: expression.expression_attribute_names,
expression_attribute_values: expression
.expression_attribute_values
.map(|values| values.into_iter().map_values(convert_av).collect()),
table_name: String::from("people"),
..QueryInput::default()
};
let output = DynamoDbClient::new(Region::UsEast1).query(input).await?;
fn convert_av(av: AwsAv) -> RusotoAv {
let mut rav = RusotoAv::default();
match av {
AwsAv::B(av) => rav.b = Some(av.into_inner().into()),
AwsAv::Bool(av) => rav.bool = av.into(),
AwsAv::Bs(av) => {
rav.bs = Some(
av.into_iter()
.map(Blob::into_inner)
.map(Into::into)
.collect(),
)
}
AwsAv::L(av) => rav.l = Some(av.into_iter().map(convert_av).collect()),
AwsAv::M(av) => rav.m = Some(av.into_iter().map_values(convert_av).collect()),
AwsAv::N(av) => rav.n = av.into(),
AwsAv::Ns(av) => rav.ns = av.into(),
AwsAv::Null(av) => rav.null = av.into(),
AwsAv::S(av) => rav.s = av.into(),
AwsAv::Ss(av) => rav.ss = av.into(),
_ => unimplemented!(
"A variant was added to aws_sdk_dynamodb::types::AttributeValue \
and not implemented here: {av:?}",
),
}
rav
}
_ = output;
Ok(())
}
}