AgentSkillsCN

appwrite-kotlin

Appwrite Kotlin SDK 技能。适用于使用 Appwrite 构建原生 Android 应用,或服务器端 Kotlin/JVM 后端时使用。涵盖客户端身份验证(邮箱、OAuth 与 Activity 集成)、数据库查询、文件上传、支持协程的实时订阅,以及通过 API 密钥实现的服务器端管理员功能——用于用户管理、数据库管理、存储与函数调用。

SKILL.md
--- frontmatter
name: appwrite-kotlin
description: Appwrite Kotlin SDK skill. Use when building native Android apps or server-side Kotlin/JVM backends with Appwrite. Covers client-side auth (email, OAuth with Activity integration), database queries, file uploads, real-time subscriptions with coroutine support, and server-side admin via API keys for user management, database administration, storage, and functions.

Appwrite Kotlin SDK

Installation

kotlin
// build.gradle.kts — Android
implementation("io.appwrite:sdk-for-android:1.8.1")

// build.gradle.kts — Server (Kotlin JVM)
implementation("io.appwrite:sdk-for-kotlin:1.8.1")

Setting Up the Client

Client-side (Android)

kotlin
import io.appwrite.Client
import io.appwrite.ID
import io.appwrite.Query
import io.appwrite.enums.OAuthProvider
import io.appwrite.services.Account
import io.appwrite.services.Realtime
import io.appwrite.services.TablesDB
import io.appwrite.services.Storage
import io.appwrite.models.InputFile

val client = Client(context)
    .setEndpoint("https://<REGION>.cloud.appwrite.io/v1")
    .setProject("[PROJECT_ID]")

Server-side (Kotlin JVM)

kotlin
import io.appwrite.Client
import io.appwrite.ID
import io.appwrite.Query
import io.appwrite.services.Users
import io.appwrite.services.TablesDB
import io.appwrite.services.Storage
import io.appwrite.services.Functions

val client = Client()
    .setEndpoint("https://<REGION>.cloud.appwrite.io/v1")
    .setProject(System.getenv("APPWRITE_PROJECT_ID"))
    .setKey(System.getenv("APPWRITE_API_KEY"))

Code Examples

Authentication (client-side)

kotlin
val account = Account(client)

// Signup
account.create(
    userId = ID.unique(),
    email = "user@example.com",
    password = "password123",
    name = "User Name"
)

// Login
val session = account.createEmailPasswordSession(
    email = "user@example.com",
    password = "password123"
)

// OAuth
account.createOAuth2Session(activity = activity, provider = OAuthProvider.GOOGLE)

// Get current user
val user = account.get()

// Logout
account.deleteSession(sessionId = "current")

User Management (server-side)

kotlin
val users = Users(client)

// Create user
val user = users.create(
    userId = ID.unique(),
    email = "user@example.com",
    password = "password123",
    name = "User Name"
)

// List users
val list = users.list()

// Get user
val fetched = users.get(userId = "[USER_ID]")

// Delete user
users.delete(userId = "[USER_ID]")

Database Operations

Note: Use TablesDB (not the deprecated Databases class) for all new code. Only use Databases if the existing codebase already relies on it or the user explicitly requests it.

kotlin
val tablesDB = TablesDB(client)

// Create database (server-side only)
val db = tablesDB.create(databaseId = ID.unique(), name = "My Database")

// Create row
val doc = tablesDB.createRow(
    databaseId = "[DATABASE_ID]",
    tableId = "[TABLE_ID]",
    rowId = ID.unique(),
    data = mapOf("title" to "Hello", "done" to false)
)

// Query rows
val results = tablesDB.listRows(
    databaseId = "[DATABASE_ID]",
    tableId = "[TABLE_ID]",
    queries = listOf(Query.equal("done", false), Query.limit(10))
)

// Get row
val row = tablesDB.getRow(databaseId = "[DATABASE_ID]", tableId = "[TABLE_ID]", rowId = "[ROW_ID]")

// Update row
tablesDB.updateRow(
    databaseId = "[DATABASE_ID]",
    tableId = "[TABLE_ID]",
    rowId = "[ROW_ID]",
    data = mapOf("done" to true)
)

// Delete row
tablesDB.deleteRow(
    databaseId = "[DATABASE_ID]",
    tableId = "[TABLE_ID]",
    rowId = "[ROW_ID]"
)

Query Methods

kotlin
// Filtering
Query.equal("field", "value")             // == (or pass list for IN)
Query.notEqual("field", "value")          // !=
Query.lessThan("field", 100)              // <
Query.lessThanEqual("field", 100)         // <=
Query.greaterThan("field", 100)           // >
Query.greaterThanEqual("field", 100)      // >=
Query.between("field", 1, 100)            // 1 <= field <= 100
Query.isNull("field")                     // is null
Query.isNotNull("field")                  // is not null
Query.startsWith("field", "prefix")       // starts with
Query.endsWith("field", "suffix")         // ends with
Query.contains("field", "sub")            // contains
Query.search("field", "keywords")         // full-text search (requires index)

// Sorting
Query.orderAsc("field")
Query.orderDesc("field")

// Pagination
Query.limit(25)                           // max rows (default 25, max 100)
Query.offset(0)                           // skip N rows
Query.cursorAfter("[ROW_ID]")             // cursor pagination (preferred)
Query.cursorBefore("[ROW_ID]")

// Selection & Logic
Query.select(listOf("field1", "field2"))
Query.or(listOf(Query.equal("a", 1), Query.equal("b", 2)))   // OR
Query.and(listOf(Query.greaterThan("age", 18), Query.lessThan("age", 65)))  // AND (default)

File Storage

kotlin
val storage = Storage(client)

// Upload file
val file = storage.createFile(
    bucketId = "[BUCKET_ID]",
    fileId = ID.unique(),
    file = InputFile.fromPath("/path/to/file.png")
)

// Get file preview
val preview = storage.getFilePreview(
    bucketId = "[BUCKET_ID]",
    fileId = "[FILE_ID]",
    width = 300,
    height = 300
)

// List files
val files = storage.listFiles(bucketId = "[BUCKET_ID]")

// Delete file
storage.deleteFile(bucketId = "[BUCKET_ID]", fileId = "[FILE_ID]")

InputFile Factory Methods

kotlin
import io.appwrite.models.InputFile

InputFile.fromPath("/path/to/file.png")              // from filesystem path
InputFile.fromBytes(byteArray, "file.png")           // from ByteArray

Teams

kotlin
val teams = Teams(client)

// Create team
val team = teams.create(teamId = ID.unique(), name = "Engineering")

// List teams
val list = teams.list()

// Create membership (invite user by email)
val membership = teams.createMembership(
    teamId = "[TEAM_ID]",
    roles = listOf("editor"),
    email = "user@example.com"
)

// List memberships
val members = teams.listMemberships(teamId = "[TEAM_ID]")

// Update membership roles
teams.updateMembership(teamId = "[TEAM_ID]", membershipId = "[MEMBERSHIP_ID]", roles = listOf("admin"))

// Delete team
teams.delete(teamId = "[TEAM_ID]")

Role-based access: Use Role.team("[TEAM_ID]") for all team members or Role.team("[TEAM_ID]", "editor") for a specific team role when setting permissions.

Real-time Subscriptions (client-side)

kotlin
val realtime = Realtime(client)

val subscription = realtime.subscribe("databases.[DATABASE_ID].tables.[TABLE_ID].rows") { response ->
    println(response.events)   // e.g. ["databases.*.tables.*.rows.*.create"]
    println(response.payload)  // the affected resource
}

// Subscribe to multiple channels
val multi = realtime.subscribe(
    "databases.[DATABASE_ID].tables.[TABLE_ID].rows",
    "buckets.[BUCKET_ID].files"
) { response -> /* ... */ }

// Cleanup
subscription.close()

Available channels:

ChannelDescription
accountChanges to the authenticated user's account
databases.[DB_ID].tables.[TABLE_ID].rowsAll rows in a table
databases.[DB_ID].tables.[TABLE_ID].rows.[ROW_ID]A specific row
buckets.[BUCKET_ID].filesAll files in a bucket
buckets.[BUCKET_ID].files.[FILE_ID]A specific file
teamsChanges to teams the user belongs to
teams.[TEAM_ID]A specific team
membershipsThe user's team memberships
functions.[FUNCTION_ID].executionsFunction execution updates

Response fields: events (array), payload (resource), channels (matched), timestamp (ISO 8601).

Serverless Functions (server-side)

kotlin
val functions = Functions(client)

// Execute function
val execution = functions.createExecution(
    functionId = "[FUNCTION_ID]",
    body = """{"key": "value"}"""
)

// List executions
val executions = functions.listExecutions(functionId = "[FUNCTION_ID]")

Writing a Function Handler (Kotlin runtime)

kotlin
// src/Main.kt — Appwrite Function entry point
import io.openruntimes.kotlin.RuntimeContext
import io.openruntimes.kotlin.RuntimeOutput

fun main(context: RuntimeContext): RuntimeOutput {
    // context.req.body        — raw body (String)
    // context.req.bodyJson    — parsed JSON (Map)
    // context.req.headers     — headers (Map)
    // context.req.method      — HTTP method
    // context.req.path        — URL path
    // context.req.query       — query params (Map)

    context.log("Processing: ${context.req.method} ${context.req.path}")

    if (context.req.method == "GET") {
        return context.res.json(mapOf("message" to "Hello from Appwrite Function!"))
    }

    return context.res.json(mapOf("success" to true))    // JSON
    // context.res.text("Hello")                          // plain text
    // context.res.empty()                                // 204
    // context.res.redirect("https://...")                 // 302
}

Server-Side Rendering (SSR) Authentication

SSR apps using Kotlin server frameworks (Ktor, Spring Boot, etc.) use the server SDK to handle auth. You need two clients:

  • Admin client — uses an API key, creates sessions, bypasses rate limits (reusable singleton)
  • Session client — uses a session cookie, acts on behalf of a user (create per-request, never share)
kotlin
import io.appwrite.Client
import io.appwrite.services.Account
import io.appwrite.enums.OAuthProvider

// Admin client (reusable)
val adminClient = Client()
    .setEndpoint("https://<REGION>.cloud.appwrite.io/v1")
    .setProject("[PROJECT_ID]")
    .setKey(System.getenv("APPWRITE_API_KEY"))

// Session client (create per-request)
val sessionClient = Client()
    .setEndpoint("https://<REGION>.cloud.appwrite.io/v1")
    .setProject("[PROJECT_ID]")

val session = call.request.cookies["a_session_[PROJECT_ID]"]
if (session != null) {
    sessionClient.setSession(session)
}

Email/Password Login (Ktor)

kotlin
post("/login") {
    val body = call.receive<LoginRequest>()
    val account = Account(adminClient)
    val session = account.createEmailPasswordSession(
        email = body.email,
        password = body.password,
    )

    // Cookie name must be a_session_<PROJECT_ID>
    call.response.cookies.append(Cookie(
        name = "a_session_[PROJECT_ID]",
        value = session.secret,
        httpOnly = true,
        secure = true,
        extensions = mapOf("SameSite" to "Strict"),
        path = "/",
    ))
    call.respond(mapOf("success" to true))
}

Authenticated Requests

kotlin
get("/user") {
    val session = call.request.cookies["a_session_[PROJECT_ID]"]
        ?: return@get call.respond(HttpStatusCode.Unauthorized)

    val sessionClient = Client()
        .setEndpoint("https://<REGION>.cloud.appwrite.io/v1")
        .setProject("[PROJECT_ID]")
        .setSession(session)

    val account = Account(sessionClient)
    val user = account.get()
    call.respond(user)
}

OAuth2 SSR Flow

kotlin
// Step 1: Redirect to OAuth provider
get("/oauth") {
    val account = Account(adminClient)
    val redirectUrl = account.createOAuth2Token(
        provider = OAuthProvider.GITHUB,
        success = "https://example.com/oauth/success",
        failure = "https://example.com/oauth/failure",
    )
    call.respondRedirect(redirectUrl)
}

// Step 2: Handle callback — exchange token for session
get("/oauth/success") {
    val account = Account(adminClient)
    val session = account.createSession(
        userId = call.parameters["userId"]!!,
        secret = call.parameters["secret"]!!,
    )

    call.response.cookies.append(Cookie(
        name = "a_session_[PROJECT_ID]", value = session.secret,
        httpOnly = true, secure = true,
        extensions = mapOf("SameSite" to "Strict"), path = "/",
    ))
    call.respond(mapOf("success" to true))
}

Cookie security: Always use httpOnly, secure, and SameSite=Strict to prevent XSS. The cookie name must be a_session_<PROJECT_ID>.

Forwarding user agent: Call sessionClient.setForwardedUserAgent(call.request.headers["User-Agent"]) to record the end-user's browser info for debugging and security.

Error Handling

kotlin
import io.appwrite.AppwriteException

try {
    val row = tablesDB.getRow(databaseId = "[DATABASE_ID]", tableId = "[TABLE_ID]", rowId = "[ROW_ID]")
} catch (e: AppwriteException) {
    println(e.message)     // human-readable message
    println(e.code)        // HTTP status code (Int)
    println(e.type)        // error type (e.g. "document_not_found")
    println(e.response)    // full response body (Map)
}

Common error codes:

CodeMeaning
401Unauthorized — missing or invalid session/API key
403Forbidden — insufficient permissions
404Not found — resource does not exist
409Conflict — duplicate ID or unique constraint
429Rate limited — too many requests

Permissions & Roles (Critical)

Appwrite uses permission strings to control access to resources. Each permission pairs an action (read, update, delete, create, or write which grants create + update + delete) with a role target. By default, no user has access unless permissions are explicitly set at the document/file level or inherited from the collection/bucket settings. Permissions are arrays of strings built with the Permission and Role helpers.

kotlin
import io.appwrite.Permission
import io.appwrite.Role

Database Row with Permissions

kotlin
val doc = tablesDB.createRow(
    databaseId = "[DATABASE_ID]",
    tableId = "[TABLE_ID]",
    rowId = ID.unique(),
    data = mapOf("title" to "Hello World"),
    permissions = listOf(
        Permission.read(Role.user("[USER_ID]")),     // specific user can read
        Permission.update(Role.user("[USER_ID]")),   // specific user can update
        Permission.read(Role.team("[TEAM_ID]")),     // all team members can read
        Permission.read(Role.any()),                 // anyone (including guests) can read
    )
)

File Upload with Permissions

kotlin
val file = storage.createFile(
    bucketId = "[BUCKET_ID]",
    fileId = ID.unique(),
    file = InputFile.fromPath("/path/to/file.png"),
    permissions = listOf(
        Permission.read(Role.any()),
        Permission.update(Role.user("[USER_ID]")),
        Permission.delete(Role.user("[USER_ID]")),
    )
)

When to set permissions: Set document/file-level permissions when you need per-resource access control. If all documents in a collection share the same rules, configure permissions at the collection/bucket level and leave document permissions empty.

Common mistakes:

  • Forgetting permissions — the resource becomes inaccessible to all users (including the creator)
  • Role.any() with write/update/delete — allows any user, including unauthenticated guests, to modify or remove the resource
  • Permission.read(Role.any()) on sensitive data — makes the resource publicly readable