mirror of https://github.com/vapor/docs.git
107 lines
4.4 KiB
Markdown
107 lines
4.4 KiB
Markdown
# Upgrading Versions
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This document provides information about changes between version and tips for migrating your projects.
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## 2.4 to 3.0
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Vapor 3 has been rewritten from the ground up to be async and event-driven. This release contains the most changes of any previous release (and most likely any future release).
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Because of this, it is recommended that to migrate your projects you start by creating a new, empty template and migrate by copy / pasting code over to the new project.
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We recommend reading the [Getting Started → Hello, world!](../getting-started/hello-world.md) section for Vapor 3 to familiarize yourself with the new APIs.
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### Async
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The biggest change in Vapor 3 is that the framework is now completely asynchronous. When you call methods that need to perform slow work like network requests or disk access instead of blocking they will now return a `Future<T>`.
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Futures are values that may not exist yet, so you cannot interact with them directly. Instead, you must use `map`/`flatMap` to access the values.
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```swift
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// vapor 2
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let res = try drop.client.get("http://vapor.codes")
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print(res.status) // HTTPStatus
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return res.status
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// vapor 3
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let f = try req.client().get("http://vapor.codes").map { res in
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print(res.http.status) // HTTPStatus
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return res.http.status
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}
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print(f) // Future<HTTPStatus>
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```
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See [Async → Getting Started](../async/getting-started.md) to learn more.
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### Application & Services
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`Droplet` has been renamed to `Application` and is now a service-container. In Vapor 2, the `Droplet` had stored properties for things you would need during development (like views, hashers, etc). In Vapor 3, this is all done via services.
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While the `Application` _is_ a service-container, you should not use it from your route closures. This is to prevent race conditions since Vapor runs on multiple threads (event loops). Instead, use the `Request` that is supplied to your route closure. This has a _copy_ of all of the application's services for you to use.
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```swift
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// vapor 2
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return try drop.view.make("myView")
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// vapor 3
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return try req.make(ViewRenderer.self).render("myView")
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// shorthand
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return try req.view().render("myView")
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```
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See [Service → Getting Started](../service/getting-started.md) to learn more.
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### Database Connections
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In Vapor 3, database connections are no longer statically accessible. This makes doing things like transactions and connection pooling much more predictable and performant.
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In order to create a `QueryBuilder` in Fluent 3, you will need access to something `DatabaseConnectable`. Most often you can just use the incoming `Request`, but you can also create connections manually if you need.
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```swift
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// vapor 2
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User.makeQuery().all()
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// vapor 3
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User.query(on: req).all()
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```
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See [DatabaseKit → Getting Started](../database-kit/getting-started.md) to learn more.
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### Migrating SQL Database
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When migrating from Fluent 2 to 3 you may need to update your `fluent` table to support the new format. In Fluent 3, the migration log table has the following changes:
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- `id` is now a `UUID`.
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- `createdAt` and `updatedAt` must now be `camelCase`.
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Depending on how your Fluent database was configured, your tables may already be in the correct format. If not, you can run the following queries to transfer the table data.
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Use this query if your column names were already set to `camelCase`.
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```sql
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ALTER TABLE fluent RENAME TO fluent_old;
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CREATE TABLE fluent
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AS (SELECT UUID() as id, name, batch, createdAt, updatedAt from fluent_old);
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```
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Use this query if your column names were `snake_case`.
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```sql
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ALTER TABLE fluent RENAME TO fluent_old;
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CREATE TABLE fluent
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AS (SELECT UUID() as id, name, batch, created_at as createdAt, updated_at as updatedAt from fluent_old);
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```
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After you have verified the table was transferred properly, you can drop the old fluent table.
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```sql
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DROP TABLE fluent_old;
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```
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### Work in progress
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This migration guide is a work in progress. Please feel free to add any migration tips here by submitting a PR.
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Join the [#upgrading-to-3](https://discordapp.com/invite/BnXmVGA) in Vapor's team chat to ask questions and get help in real time.
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Also check out [Getting started with Vapor 3](https://engineering.nodesagency.com/articles/Vapor/Getting-started-with-Vapor-3/), an in-depth article about the differences between Vapor 2 and 3. This article was written by two developers from an app development company using Vapor.
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