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+---
+date: "2019-04-15T17:29:00+08:00"
+title: "Advanced: Migrations Interfaces"
+slug: "migrations-interfaces"
+weight: 30
+toc: true
+draft: false
+menu:
+  sidebar:
+    parent: "advanced"
+    name: "Migrations Interfaces"
+    weight: 55
+    identifier: "migrations-interfaces"
+---
+
+# Migration Features
+
+The new migration features were introduced in Gitea 1.9.0. It defines two interfaces to support migrating 
+repositories data from other git host platforms to gitea or, in the future migrating gitea data to other 
+git host platforms. Currently, only the migrations from github via APIv3 to Gitea is implemented.
+
+First of all, Gitea defines some standard objects in packages `modules/migrations/base`. They are
+ `Repository`, `Milestone`, `Release`, `Label`, `Issue`, `Comment`, `PullRequest`.
+
+## Downloader Interfaces
+
+To migrate from a new git host platform, there are two steps to be updated.
+
+- You should implement a `Downloader` which will get all kinds of repository informations.
+- You should implement a `DownloaderFactory` which is used to detect if the URL matches and 
+create a Downloader.
+- You'll need to register the `DownloaderFactory` via `RegisterDownloaderFactory` on init.
+
+```Go
+type Downloader interface {
+	GetRepoInfo() (*Repository, error)
+	GetMilestones() ([]*Milestone, error)
+	GetReleases() ([]*Release, error)
+	GetLabels() ([]*Label, error)
+	GetIssues(start, limit int) ([]*Issue, error)
+	GetComments(issueNumber int64) ([]*Comment, error)
+	GetPullRequests(start, limit int) ([]*PullRequest, error)
+}
+```
+
+```Go
+type DownloaderFactory interface {
+	Match(opts MigrateOptions) (bool, error)
+	New(opts MigrateOptions) (Downloader, error)
+}
+```
+
+## Uploader Interface
+
+Currently, only a `GiteaLocalUploader` is implemented, so we only save downloaded 
+data via this `Uploader` on the local Gitea instance. Other uploaders are not supported
+and will be implemented in future.
+
+```Go
+// Uploader uploads all the informations
+type Uploader interface {
+	CreateRepo(repo *Repository, includeWiki bool) error
+	CreateMilestone(milestone *Milestone) error
+	CreateRelease(release *Release) error
+	CreateLabel(label *Label) error
+	CreateIssue(issue *Issue) error
+	CreateComment(issueNumber int64, comment *Comment) error
+	CreatePullRequest(pr *PullRequest) error
+	Rollback() error
+}
+
+```
+\ No newline at end of file