从Dify源码学习flask开发

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[api/]
├── configs               // 配置信息
├── constants             // 常量设置
├── controllers           // API路由和请求处理逻辑
├── core                  // 核心应用和工具
├── docker                // Docker & 容器和相关配置
├── events                // 事件处理
├── extensions            // 插件
├── fields                // 序列化字段定义
├── libs                  // 可复用的库
├── migrations            // 数据库迁移脚本
├── models                // 数据库模型定义
├── services              // 业务处理逻辑
├── template              // 模板
├── tasks                 // 异步任务和后台作业处理
└── tests                 // 测试

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# /api/app_factory.py
for ext in extensions:
    short_name = ext.__name__.split(".")[-1]
    is_enabled = ext.is_enabled() if hasattr(ext, "is_enabled") else True
    if not is_enabled:
        if dify_config.DEBUG:
            logging.info(f"Skipped {short_name}")
        continue

    start_time = time.perf_counter()
    ext.init_app(app)
    end_time = time.perf_counter()
    if dify_config.DEBUG:
        logging.info(f"Loaded {short_name} ({round((end_time - start_time) * 1000, 2)} ms)")

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# api/dify_app.py
from flask import Flask


class DifyApp(Flask):
    pass

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# /api/app_factory.py
from dify_app import DifyApp


# ----------------------------
# Application Factory Function
# ----------------------------
def create_flask_app_with_configs() -> DifyApp:
    """
    create a raw flask app
    with configs loaded from .env file
    """
    dify_app = DifyApp(__name__)
    dify_app.config.from_mapping(dify_config.model_dump())

    # add before request hook
    @dify_app.before_request
    def before_request():
        # add an unique identifier to each request
        RecyclableContextVar.increment_thread_recycles()

    return dify_app

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# /api/app_factory.py
def create_app() -> DifyApp:
    start_time = time.perf_counter()
    app = create_flask_app_with_configs()
    initialize_extensions(app)
    end_time = time.perf_counter()
    if dify_config.DEBUG:
        logging.info(f"Finished create_app ({round((end_time - start_time) * 1000, 2)} ms)")
    return app

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# api/extensions/ext_mail.py
import logging
from typing import Optional

from flask import Flask

from configs import dify_config
from dify_app import DifyApp


class Mail:
    def __init__(self):
        self._client = None
        self._default_send_from = None

    def is_inited(self) -> bool:
        return self._client is not None

    def init_app(self, app: Flask):
        mail_type = dify_config.MAIL_TYPE
        if not mail_type:
            logging.warning("MAIL_TYPE is not set")
            return

        if dify_config.MAIL_DEFAULT_SEND_FROM:
            self._default_send_from = dify_config.MAIL_DEFAULT_SEND_FROM

        match mail_type:
            case "resend":
                ...
            case "smtp":
                ...

def is_enabled() -> bool:
    return dify_config.MAIL_TYPE is not None and dify_config.MAIL_TYPE != ""


def init_app(app: DifyApp):
    mail.init_app(app)


mail = Mail()

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# /api/app_factory.py
def initialize_extensions(app: DifyApp):
    from extensions import (
        ext_app_metrics,
        ext_blueprints,
        ...
        ext_mail,
        ext_warnings,
    )

    extensions = [
        ext_app_metrics,
        ext_blueprints,
        ...
        ext_mail,
        ext_warnings,
    ]
    for ext in extensions:
        short_name = ext.__name__.split(".")[-1]
        is_enabled = ext.is_enabled() if hasattr(ext, "is_enabled") else True
        if not is_enabled:
            if dify_config.DEBUG:
                logging.info(f"Skipped {short_name}")
            continue

        start_time = time.perf_counter()
        ext.init_app(app)
        end_time = time.perf_counter()
        if dify_config.DEBUG:
            logging.info(f"Loaded {short_name} ({round((end_time - start_time) * 1000, 2)} ms)")

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# api/.env.example
# Your App secret key will be used for securely signing the session cookie
# Make sure you are changing this key for your deployment with a strong key.
# You can generate a strong key using `openssl rand -base64 42`.
# Alternatively you can set it with `SECRET_KEY` environment variable.
SECRET_KEY=

# Console API base URL
CONSOLE_API_URL=http://127.0.0.1:5001
CONSOLE_WEB_URL=http://127.0.0.1:3000

# Service API base URL
SERVICE_API_URL=http://127.0.0.1:5001

# Web APP base URL
APP_WEB_URL=http://127.0.0.1:3000

# Files URL
FILES_URL=http://127.0.0.1:5001

# The time in seconds after the signature is rejected
FILES_ACCESS_TIMEOUT=300

# Access token expiration time in minutes
ACCESS_TOKEN_EXPIRE_MINUTES=60

# Refresh token expiration time in days
REFRESH_TOKEN_EXPIRE_DAYS=30
# ...

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# api/configs/app_config.py
class DifyConfig(
    # Packaging info
    PackagingInfo,
    # Deployment configs
    DeploymentConfig,
    ...
):
    model_config = SettingsConfigDict(
        # read from dotenv format config file
        env_file=".env",
        env_file_encoding="utf-8",
        # ignore extra attributes
        extra="ignore",
    )

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# api/configs/packaging/__init__.py
from pydantic import Field
from pydantic_settings import BaseSettings


class PackagingInfo(BaseSettings):
    """
    Packaging build information
    """

    CURRENT_VERSION: str = Field(
        description="Dify version",
        default="1.4.2",
    )

    COMMIT_SHA: str = Field(
        description="SHA-1 checksum of the git commit used to build the app",
        default="",
    )

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# api/libs/exception.py
from typing import Optional

from werkzeug.exceptions import HTTPException


class BaseHTTPException(HTTPException):
    error_code: str = "unknown"
    data: Optional[dict] = None

    def __init__(self, description=None, response=None):
        super().__init__(description, response)

        self.data = {
            "code": self.error_code,
            "message": self.description,
            "status": self.code,
        }

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# api/controllers/console/error.py
from libs.exception import BaseHTTPException


class AlreadySetupError(BaseHTTPException):
    error_code = "already_setup"
    description = "Dify has been successfully installed. Please refresh the page or return to the dashboard homepage."
    code = 403


class NotSetupError(BaseHTTPException):
    error_code = "not_setup"
    description = (
        "Dify has not been initialized and installed yet. "
        "Please proceed with the initialization and installation process first."
    )
    code = 401


class NotInitValidateError(BaseHTTPException):
    error_code = "not_init_validated"
    description = "Init validation has not been completed yet. Please proceed with the init validation process first."
    code = 401