第 2 章 · 路由

from flask import Flask, jsonify

app = Flask(__name__)
app.json.ensure_ascii = False


@app.route("/")
def index():
    return jsonify({"msg": "古典文学网 API 已启动"})


@app.route("/api/banner/list")
def banner_list():
    """首页轮播图：对应 banner 表的三条种子数据"""
    return jsonify({
        "code": 200,
        "msg": "success",
        "data": [
            {"id": 1, "title": "品读古典文学，涵养中国心灵",
             "image": "/static/images/banner1.jpg"},
            {"id": 2, "title": "一场跨越千年的对话",
             "image": "/static/images/banner2.jpg"},
            {"id": 3, "title": "写下你的书评，与同好相遇",
             "image": "/static/images/banner3.jpg"},
        ],
    })


@app.route("/api/category/list")
def category_list():
    """分类列表：对应 category 表的种子数据"""
    return jsonify({
        "code": 200,
        "msg": "success",
        "data": [
            {"id": 1, "name": "唐诗", "description": "唐代诗歌，格律严谨、气象恢宏"},
            {"id": 2, "name": "宋词", "description": "宋代词作，婉约与豪放并存"},
            {"id": 3, "name": "元曲", "description": "元代散曲与杂剧，通俗生动"},
            {"id": 4, "name": "散文", "description": "先秦至明清的散文名篇"},
            {"id": 5, "name": "小说", "description": "章回体与笔记体小说"},
        ],
    })


if __name__ == "__main__":
    app.run(debug=True)

# ① int：只匹配整数（最常用），URL 里出现非数字直接 404
@app.route("/api/article/detail/<int:aid>")
def article_detail(aid):
    # 进来的 aid 已经是 int，可以直接参与运算，不用 int() 转换
    return jsonify({"code": 200, "msg": "success", "data": {"id": aid}})


# ② string：匹配一段不含斜杠的文本（默认类型，不写也行）
@app.route("/api/user/<string:username>")
def user_info(username):
    return jsonify({"code": 200, "msg": "success", "data": {"username": username}})


# ③ float：匹配小数
@app.route("/api/rank/<float:score>")
def rank(score):
    return jsonify({"code": 200, "msg": "success", "data": {"score": score}})


# ④ path：允许匹配带斜杠的完整路径，适合文件下载
@app.route("/api/download/<path:filepath>")
def download(filepath):
    return jsonify({"code": 200, "msg": "success", "data": {"filepath": filepath}})

from flask import Flask, jsonify, request

app = Flask(__name__)
app.json.ensure_ascii = False


# 写法一：一个接口只干一件事，最清晰 —— 推荐
@app.route("/api/comment/list", methods=["GET"])
def comment_list():
    return jsonify({"code": 200, "msg": "success",
                    "data": {"list": [], "total": 0, "page": 1, "page_size": 10}})


@app.route("/api/comment/add", methods=["POST"])
def comment_add():
    data = request.get_json()
    return jsonify({"code": 200, "msg": "发表成功", "data": {"comment_id": 9}})


# 写法二：同一个路径、同一个函数处理两种方法，用 request.method 分流
@app.route("/api/user/profile", methods=["GET", "PUT"])
def user_profile():
    if request.method == "GET":
        return jsonify({"code": 200, "msg": "success",
                        "data": {"id": 3, "username": "zhangsan", "nickname": "张三"}})
    # 走到这里就是 PUT：修改资料
    return jsonify({"code": 200, "msg": "修改成功", "data": None})

from flask import Flask, jsonify, url_for

app = Flask(__name__)
app.json.ensure_ascii = False


@app.route("/api/article/detail/<int:aid>")
def article_detail(aid):
    return jsonify({"code": 200, "msg": "success", "data": {"id": aid}})


@app.route("/api/article/list")
def article_list():
    rows = [
        {"id": 1, "title": "静夜思", "author": "李白"},
        {"id": 3, "title": "念奴娇·赤壁怀古", "author": "苏轼"},
    ]
    for row in rows:
        # 不用手拼 "/api/article/detail/" + str(row["id"])
        row["detail_url"] = url_for("article_detail", aid=row["id"])

    return jsonify({
        "code": 200,
        "msg": "success",
        "data": {"list": rows, "total": 6, "page": 1, "page_size": 10},
    })


@app.route("/")
def index():
    # 静态文件也能生成地址：static 是 Flask 自带的端点
    avatar = url_for("static", filename="upload/avatar/3.png")
    # 额外参数会变成查询字符串：/api/article/list?page=2
    more = url_for("article_list", page=2)
    return jsonify({"code": 200, "msg": "success",
                    "data": {"avatar": avatar, "more": more}})

# 规则带尾部斜杠：访问不带斜杠的地址时，Flask 会自动 308 重定向过去
@app.route("/article/")
def article_page():
    return "带斜杠的规则"

# 规则不带尾部斜杠：访问带斜杠的地址会直接 404，没有任何提示
@app.route("/article")
def article_page():
    return "不带斜杠的规则"

@app.route("/api/article/detail/<int:aid>", methods=["GET"])
def article_detail(aid):
    """作品详情：先用手写数据，第 6 章换成查 article 表"""
    articles = {
        1: {"id": 1, "title": "静夜思", "author": "李白", "dynasty": "唐",
            "category_name": "唐诗", "views": 329, "likes": 42},
        3: {"id": 3, "title": "念奴娇·赤壁怀古", "author": "苏轼", "dynasty": "宋",
            "category_name": "宋词", "views": 412, "likes": 58},
    }
    article = articles.get(aid)
    if article is None:
        # 业务失败也返回 HTTP 200，成败看 code —— 按接口文档的统一约定
        return jsonify({"code": 404, "msg": "作品不存在", "data": None})

    return jsonify({"code": 200, "msg": "success", "data": article})