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#![deny(warnings, missing_docs)] //! [DynamoDB] is an AWS database that stores key/value and document data. //! //! The most common way to access DynamoDB data from Rust is to use //! [rusoto_dynamodb]'s [get_item], [put_item], and related methods. //! //! **serde_dynamo** provides a way to serialize and deserialize between data stored in these //! [`Item`]s and strongly-typed Rust data structures. //! //! //! ## The full power of serde //! //! **serde_dynamo** supports the full power of [serde]. //! //! Most uses of DynamoDB will involve simple structs mapping keys to values in type-safe ways. //! //! ``` //! # use serde::{Serialize, Deserialize}; //! # //! #[derive(Serialize, Deserialize)] //! pub struct User { //! id: String, //! name: String, //! age: u8, //! } //! ``` //! //! More advanced usage – including [flattening], [adjacently tagged enums], and [untagged enums] – //! is fully supported. //! //! ``` //! # use chrono::{DateTime, Utc}; //! # use serde::{Serialize, Deserialize}; //! # use serde_dynamo::to_item; //! # //! #[derive(Serialize, Deserialize)] //! struct Message { //! id: String, //! #[serde(flatten)] //! message_type: MessageType, //! sent: DateTime<Utc>, //! } //! //! /// What type of message this is. //! /// //! /// By the power of Rust enums and serde serializating, we can guarantee that we _either_ have //! /// an email with all of its required fields, _or_ an SMS with all of its required fields. //! #[derive(Serialize, Deserialize)] //! #[serde(rename_all = "snake_case", tag = "message_type", content = "message_payload")] //! enum MessageType { //! Email(Email), //! Sms(Sms), //! } //! //! #[derive(Serialize, Deserialize)] //! struct Email { //! email: String, //! #[serde(skip_serializing_if = "Option::is_none")] //! name: Option<String>, //! subject: String, //! body: String, //! } //! //! #[derive(Serialize, Deserialize)] //! #[serde(rename_all = "snake_case")] //! struct Sms { //! phone_number: String, //! body: String, //! } //! //! # fn test() -> Result<(), Box<dyn std::error::Error>> { //! let input = r#" //! { //! "id": "HWCqBFBG2Gl4", //! "message_type": "sms", //! "message_payload": { //! "phone_number": "5551234567", //! "body": "Good morning!" //! }, //! "sent": "1985-04-21T11:12:13Z" //! } //! "#; //! let message: Message = serde_json::from_str(input)?; //! let item = to_item(message)?; //! # Ok(()) //! # } //! # test().unwrap() //! ``` //! //! //! ## Parsing items as strongly-typed data structures. //! //! [`Item`]s received from a [rusoto_dynamodb] call can be run through [`from_items`]. //! //! ``` //! # use rusoto_dynamodb::{DynamoDb, DynamoDbClient, ScanInput}; //! # use serde::{Serialize, Deserialize}; //! # use serde_dynamo::from_items; //! # //! # async fn scan(client: &DynamoDbClient) -> Result<(), Box<dyn std::error::Error>> { //! #[derive(Serialize, Deserialize)] //! pub struct User { //! id: String, //! name: String, //! age: u8, //! }; //! //! // Get documents from DynamoDB //! let input = ScanInput { //! table_name: "users".to_string(), //! ..ScanInput::default() //! }; //! let result = client.scan(input).await?; //! //! // And deserialize them as strongly-typed data structures //! if let Some(items) = result.items { //! let users: Vec<User> = from_items(items)?; //! println!("Got {} users", users.len()); //! } //! # Ok(()) //! # } //! ``` //! //! Alternatively, to deserialize one item at a time, [`from_item`] can be used. //! //! ``` //! # use rusoto_dynamodb::{DynamoDb, DynamoDbClient, ScanInput}; //! # use serde::{Serialize, Deserialize}; //! # use serde_dynamo::from_item; //! # //! # async fn scan(client: &DynamoDbClient) -> Result<(), Box<dyn std::error::Error>> { //! #[derive(Serialize, Deserialize)] //! pub struct User { //! id: String, //! name: String, //! age: u8, //! }; //! //! // Get documents from DynamoDB //! let input = ScanInput { //! table_name: "users".to_string(), //! ..ScanInput::default() //! }; //! let result = client.scan(input).await?; //! //! // And deserialize them as strongly-typed data structures //! for item in result.items.unwrap() { //! let user: User = from_item(item)?; //! println!("{} is {}", user.name, user.age); //! } //! # Ok(()) //! # } //! ``` //! //! //! ## Creating items by serializing data structures //! //! Writing an entire data structure to DynamoDB typically involves using [`to_item`] to serialize //! it. //! //! ``` //! # use rusoto_dynamodb::{DynamoDb, DynamoDbClient, PutItemInput}; //! # use serde::{Serialize, Deserialize}; //! # use serde_dynamo::to_item; //! # //! # async fn put(client: &DynamoDbClient) -> Result<(), Box<dyn std::error::Error>> { //! #[derive(Serialize, Deserialize)] //! pub struct User { //! id: String, //! name: String, //! age: u8, //! }; //! //! // Create a user //! let user = User { //! id: "fSsgVtal8TpP".to_string(), //! name: "Arthur Dent".to_string(), //! age: 42, //! }; //! //! // Turn it into an item that rusoto understands //! let item = to_item(user)?; //! //! // And write it! //! let input = PutItemInput { //! table_name: "users".to_string(), //! item: item, //! ..PutItemInput::default() //! }; //! client.put_item(input).await?; //! # Ok(()) //! # } //! ``` //! //! //! ## Using to_attribute_value for more control //! //! In some circumstances, building [rusoto_dynamodb::AttributeValue]s directly is required. //! //! For example, when generating a key to supply to [get_item]. //! //! ``` //! use maplit::hashmap; //! use serde_dynamo::to_attribute_value; //! # use rusoto_dynamodb::{DynamoDb, DynamoDbClient, GetItemInput}; //! # //! # async fn get(client: &DynamoDbClient) -> Result<(), Box<dyn std::error::Error>> { //! # //! # struct User { id: String }; //! # let user = User { id: "fSsgVtal8TpP".to_string() }; //! //! // Create the unique key of the record in DynamoDB in a way rusoto understands //! let key = hashmap! { //! "id".into() => to_attribute_value(&user.id)?, //! }; //! //! // And get the record //! let input = GetItemInput { //! table_name: "users".to_string(), //! key: key, //! ..GetItemInput::default() //! }; //! client.get_item(input).await?; //! # Ok(()) //! # } //! ``` //! //! Or when generating attribute values in a [query] call. //! //! ``` //! use maplit::hashmap; //! use serde_dynamo::to_attribute_value; //! # use rusoto_dynamodb::{DynamoDb, DynamoDbClient, QueryInput}; //! # //! # async fn query(client: &DynamoDbClient) -> Result<(), Box<dyn std::error::Error>> { //! # let user_type = "user"; //! # let yesterday = "1985-04-21"; //! //! // Declare all of the expression inputs for a query call //! let expression_attribute_values = hashmap! { //! ":user_type".to_string() => to_attribute_value(user_type)?, //! ":last_login".to_string() => to_attribute_value(yesterday)?, //! }; //! //! // And execute the query //! let input = QueryInput { //! table_name: "users".to_string(), //! index_name: Some("by_type_and_last_login".to_string()), //! key_condition_expression: Some("user_type = :user_type AND last_login > :last_login".to_string()), //! expression_attribute_values: Some(expression_attribute_values), //! ..QueryInput::default() //! }; //! client.query(input).await?; //! # Ok(()) //! # } //! ``` //! //! ## JSON //! //! DynamoDB's items share strong similarities with JSON, and it is very common to store JSON data //! in DynamoDB either directly or as a subfield. //! //! To support this, **serde_dynamo** supports serializing JSON just like any other Rust data //! structure. //! //! ``` //! # use serde::{Serialize, Deserialize}; //! # //! #[derive(Serialize, Deserialize)] //! struct IncludesJson { //! id: String, //! data: serde_json::Value, //! } //! ``` //! //! In addition, **serde_dynamo** also maps strongly-typed data structures nearly identically as //! [serde_json]. This means that, in almost all cases, serializing to JSON first and then to an //! [`Item`] will result in the exact same representation as serializing directly to an `Item`. //! (The caveat here is for byte data, which loses fidelity because JSON doesn't support byte data //! natively, but DynamoDB does.) //! //! ``` //! # use serde_dynamo::to_item; //! # use serde::{Serialize, Deserialize}; //! # //! # #[derive(Clone, Serialize, Deserialize)] //! # struct User { //! # name: String, //! # age: u8, //! # } //! # //! # fn equivalence() -> Result<(), Box<dyn std::error::Error>> { //! let user = User { //! name: "Arthur Dent".to_string(), //! age: 42, //! }; //! //! // Serialize directly from the data structure to an item //! let direct_item = to_item(user.clone())?; //! //! // Serialize indirectly through JSON //! let json = serde_json::to_value(user.clone())?; //! let indirect_item = to_item(json)?; //! //! // The result should be the same! //! assert_eq!(direct_item, indirect_item); //! # Ok(()) //! # } //! ``` //! //! [DynamoDB]: https://aws.amazon.com/dynamodb/ //! [rusoto_dynamodb]: https://docs.rs/rusoto_dynamodb //! [get_item]: https://docs.rs/rusoto_dynamodb/0.45.0/rusoto_dynamodb/trait.DynamoDb.html#tymethod.get_item //! [put_item]: https://docs.rs/rusoto_dynamodb/0.45.0/rusoto_dynamodb/trait.DynamoDb.html#tymethod.put_item //! [query]: https://docs.rs/rusoto_dynamodb/0.45.0/rusoto_dynamodb/trait.DynamoDb.html#tymethod.query //! [serde]: https://docs.rs/serde //! [serde_json]: https://docs.rs/serde_json //! [flattening]: https://serde.rs/attr-flatten.html //! [adjacently tagged enums]: https://serde.rs/enum-representations.html#adjacently-tagged //! [untagged enums]: https://serde.rs/enum-representations.html#untagged //! [rusoto_dynamodb::AttributeValue]: https://docs.rs/rusoto_dynamodb/0.45.0/rusoto_dynamodb/struct.AttributeValue.html use rusoto_dynamodb::AttributeValue; use std::collections::HashMap; mod de; mod error; mod ser; pub use de::{from_attribute_value, from_item, from_items, Deserializer}; pub use error::{Error, Result}; pub use ser::{to_attribute_value, to_item, Serializer}; use error::ErrorImpl; /// An "Item" used in [rusoto_dynamodb]'s [get_item], [write_item], [put_item], etc. /// /// Nowhere in rusoto_dynamodb is this type named explicitely, so we name it here to be clear about /// exactly what is being taken in and being returned. /// /// [rusoto_dynamodb]: https://docs.rs/rusoto_dynamodb /// [get_item]: https://docs.rs/rusoto_dynamodb/0.45.0/rusoto_dynamodb/trait.DynamoDb.html#tymethod.get_item /// [write_item]: https://docs.rs/rusoto_dynamodb/0.45.0/rusoto_dynamodb/trait.DynamoDb.html#tymethod.write_item /// [put_item]: https://docs.rs/rusoto_dynamodb/0.45.0/rusoto_dynamodb/trait.DynamoDb.html#tymethod.put_item pub type Item = HashMap<String, AttributeValue>; #[cfg(test)] mod tests;