# Using the Request Directly

Up to now, you have been declaring the parts of the request that you need with their types.

Taking data from:

* The path as parameters.
* Headers.
* Cookies.
* etc.

And by doing so, **FastAPI** is validating that data, converting it and generating documentation for your API automatically.

But there are situations where you might need to access the `Request` object directly.

Sebastián Ramírez <******@****.***> 1728247014 +0200

Sebastián Ramírez <******@****.***> 1728247014 +0200

Sebastián Ramírez <******@****.***> 1728247014 +0200

Sebastián Ramírez <******@****.***> 1728247014 +0200

# ADR-0002 - Avoid using Java serialization

## Date

2012-12-01

## Context

In Gradle we often need to serialize in-memory objects for caching, or to transmit them across process barriers, etc.
Java serialization is one way to implement this, however, despite its simplicity of implementation, it has several drawbacks:

- **Performance:**
Java's built-in serialization mechanism is often slower compared to other serialization solutions.

		builder.WriteString("JOIN ")
		builder.WriteQuoted(join.Table)

		if len(join.ON.Exprs) > 0 {
			builder.WriteString(" ON ")
			join.ON.Build(builder)
		} else if len(join.Using) > 0 {
			builder.WriteString(" USING (")
			for idx, c := range join.Using {
				if idx > 0 {
					builder.WriteByte(',')
				}
				builder.WriteQuoted(c)
			}
			builder.WriteByte(')')
		}
	}

				},
			},
			sql: "CROSS JOIN `user` ON `user_info`.`user_id` = `users`.`id`",
		},
		{
			name: "USING",
			join: clause.Join{
				Type:  clause.InnerJoin,
				Table: clause.Table{Name: "user"},
				Using: []string{"id"},
			},
			sql: "INNER JOIN `user` USING (`id`)",
		},
		{
			name: "Expression",
			join: clause.Join{
				// Invalid
				Type:  clause.LeftJoin,

## Recap

* Import `FastAPI`.
* Create an `app` instance.
* Write a **path operation decorator** using decorators like `@app.get("/")`.
* Define a **path operation function**; for example, `def root(): ...`.

Traditional retrieval of objects is always as whole entities, i.e GetObject for a 5 GiB object, will always return 5 GiB of data. S3 Select API allows us to retrieve a subset of data by using simple SQL expressions. By using Select API to retrieve only the data needed by the application, drastic performance improvements can be achieved.

You can use the Select API to query objects with following features: