apewer-dotnet/Apewer.Web/Internals/ApiHelper.cs

using Apewer.Network;
using Apewer.Web;
using System;
using System.Collections.Generic;
using System.Text;

namespace Apewer.Internals
{

    internal static class ApiHelper
    {

        #region Cookies

        // https://developer.mozilla.org/zh-CN/docs/Web/HTTP/Headers/Set-Cookie

        // <cookie-name> 可以是除了控制字符 (CTLs)、空格 (spaces) 或制表符 (tab)之外的任何 US-ASCII 字符。
        // 同时不能包含以下分隔字符： ( ) < > @ , ; : \ " /  [ ] ? = { }.

        // <cookie-value> 是可选的，如果存在的话，那么需要包含在双引号里面。
        // 支持除了控制字符（CTLs）、空格（whitespace）、双引号（double quotes）、逗号（comma）、分号（semicolon）以及反斜线（backslash）之外的任意 US-ASCII 字符。

        // 关于编码：许多应用会对 cookie 值按照URL编码（URL encoding）规则进行编码，但是按照 RFC 规范，这不是必须的。
        // 不过满足规范中对于 <cookie-value> 所允许使用的字符的要求是有用的。

        internal static StringPairs ParseCookies(StringPairs headers)
        {
            var cookies = new StringPairs();
            if (headers == null) return cookies;

            var hvs = headers.GetValues("cookie", true, false);
            foreach (var hv in hvs)
            {
                if (string.IsNullOrEmpty(hv)) continue;
                var lines = hv.Split(';');
                foreach (var line in lines)
                {
                    var e = line.IndexOf("=");
                    if (e < 0) continue;
                    var name = TextUtility.Left(line, e, true);
                    var value = TextUtility.Right(line, line.Length - e - 1, true);
                    if (string.IsNullOrEmpty(name)) continue;
                    if (string.IsNullOrEmpty(value)) continue;
                    cookies.Add(name, value);
                }
            }

            return cookies;
        }

        // 生成 Response 头中 Set-Cookie 的值。
        internal static string SetCookie(IEnumerable<KeyValuePair<string, string>> cookies)
        {
            if (cookies == null) return null;

            var ps = new List<string>();
            foreach (var kvp in cookies)
            {
                var k = kvp.Key ?? "";
                var v = kvp.Value ?? "";
                if (k.IsEmpty()) continue;
                ps.Add(TextUtility.Merge(k, "=", v));
            }

            if (ps.Count < 1) return null;

            var value = TextUtility.Join("; ", ps);
            return value;
        }

        #endregion

        #region ApiFunction Parameterse

        // 为带有形参的 Function 准备实参。
        internal static object[] ReadParameters(ApiRequest request, ApiFunction function)
        {
            if (request == null || function == null) return null;

            var pis = function.Parameters;
            if (pis == null) return null;

            var count = pis.Length;
            if (count < 1) return null;

            // 当 Function 仅有一个参数时，尝试生成模型。
            if (count == 1)
            {
                if (function.ParamIsRecord)
                {
                    try
                    {
                        var record = Activator.CreateInstance(pis[0].ParameterType);
                        Json.Object(record, request.Data, true, null, true);
                        return new object[] { record };
                    }
                    catch { }
                    return new object[] { null };
                }
                // 未知类型的参数，继续使用通用方法获取。
            }

            var ps = new object[count];
            for (var i = 0; i < count; i++)
            {
                var name = pis[i].Name;
                var type = pis[i].ParameterType;
                var text = ApiUtility.Parameter(request, name);
                ps[i] = ReadParameter(text, type);
            }
            return ps;
        }

        static object ReadParameter(string text, Type type)
        {
            if (type.Equals(typeof(object)) || type.Equals(typeof(string))) return text;
            if (type.Equals(typeof(byte[]))) return TextUtility.FromBase64(text);
            if (type.Equals(typeof(float))) return NumberUtility.Single(text);
            if (type.Equals(typeof(double))) return NumberUtility.Double(text);
            if (type.Equals(typeof(decimal))) return NumberUtility.Decimal(text);
            if (type.Equals(typeof(byte))) return NumberUtility.Byte(text);
            if (type.Equals(typeof(sbyte))) return NumberUtility.SByte(text);
            if (type.Equals(typeof(short))) return NumberUtility.Int16(text);
            if (type.Equals(typeof(ushort))) return NumberUtility.UInt16(text);
            if (type.Equals(typeof(int))) return NumberUtility.Int32(text);
            if (type.Equals(typeof(uint))) return NumberUtility.UInt32(text);
            if (type.Equals(typeof(long))) return NumberUtility.Int64(text);
            if (type.Equals(typeof(ulong))) return NumberUtility.UInt64(text);
            return type.IsValueType ? Activator.CreateInstance(type) : null;
        }

        #endregion

        #region Enumerate Entries

        internal static Json Enumerate(IEnumerable<ApiApplication> applications, ApiOptions options)
        {
            var list = Json.NewArray();
            var count = 0;
            if (applications != null)
            {
                foreach (var app in applications)
                {
                    if (app == null) continue;
                    if (app.Hidden) continue;
                    list.AddItem(app.ToJson(options));
                    count = count + 1;
                }
            }
            var json = Json.NewObject();
            json.SetProperty("count", count);
            json.SetProperty("list", list);
            return json;
        }

        internal static Json Enumerate(IEnumerable<ApiFunction> functions, ApiOptions options)
        {
            var count = 0;
            var list = Json.NewArray();
            if (functions != null)
            {
                foreach (var func in functions)
                {
                    if (func == null) continue;
                    if (func.Hidden) continue;
                    list.AddItem(func.ToJson(options));
                    count = count + 1;
                }
            }
            var json = Json.NewObject();
            json.SetProperty("count", count);
            json.SetProperty("list", list);
            return json;
        }

        #endregion

        #region Request

        internal static ApiRequest GetRequest(ApiProvider provider, ApiOptions options, HttpMethod method, Uri url)
        {
            // 创建数据对象。
            var request = new ApiRequest();

            // Http Method。
            request.Method = method;

            // 基本信息。
            var ip = provider.GetClientIP() ?? null;
            var headers = provider.GetHeaders() ?? new StringPairs();
            request.Headers = headers;
            request.IP = ip;
            request.Url = url;
            request.Referrer = provider.GetReferrer();
            request.Parameters = ApiUtility.Parameters(url.Query);

            // Headers。
            request.UserAgent = ApiUtility.UserAgent(headers);
            request.Cookies = ParseCookies(headers) ?? new StringPairs();

            // 匹配 API。
            var application = null as string;
            var function = null as string;
            var random = null as string;
            var ticket = null as string;
            var session = null as string;
            var page = null as string;

            // 解析 POST 请求。
            if (request.Method == HttpMethod.POST)
            {
                var preRead = provider.PreRead();
                if (string.IsNullOrEmpty(preRead))
                {
                    var post = null as byte[];
                    var length = 0L;
                    var max = options.MaxRequestBody;
                    if (max == 0) post = new byte[0];
                    else if (max < 0) post = provider.RequestBody().Read();
                    else
                    {
                        length = provider.GetContentLength();
                        if (length <= max) post = provider.RequestBody().Read();
                    }

                    length = post == null ? 0 : post.Length;
                    if (length > 1)
                    {
                        request.PostData = post;
                        if (length < 104857600)
                        {
                            var text = TextUtility.FromBytes(post);
                            request.PostText = text;

                            // 尝试解析 Json，首尾必须是“{}”或“[]”。
                            var first = post[0];
                            var last = post[length - 1];
                            if ((first == 123 && last == 125) || (first == 91 && last == 93))
                            {
                                var json = Json.From(text);
                                if (json != null && json.IsObject)
                                {
                                    application = json["application"];
                                    function = json["function"];
                                    random = json["random"];
                                    ticket = json["ticket"];
                                    session = json["session"];
                                    page = json["page"];

                                    var data = json.GetProperty("data");
                                    request.PostJson = json;
                                    request.Data = data ?? Json.NewObject();
                                }
                            }
                        }
                    }
                }
            }

            // 解析 URL 参数。
            // URL 参数的优先级应高于 URL 路径，以避免反向代理产生的路径问题。
            var urlParameters = ApiUtility.Parameters(request.Url.Query);
            if (string.IsNullOrEmpty(application)) application = urlParameters.GetValue("application");
            if (string.IsNullOrEmpty(function)) function = urlParameters.GetValue("function");
            if (string.IsNullOrEmpty(random)) random = urlParameters.GetValue("random");
            if (string.IsNullOrEmpty(ticket)) ticket = urlParameters.GetValue("ticket");
            if (string.IsNullOrEmpty(session)) session = urlParameters.GetValue("session");
            if (string.IsNullOrEmpty(page)) page = urlParameters.GetValue("page");

            // 从 Cookie 中获取 Ticket。
            var cookies = request.Cookies;
            if (string.IsNullOrEmpty(ticket)) ticket = cookies.GetValue("ticket");

            // 最后检查 URL 路径。
            var paths = (request.Url.AbsolutePath ?? "").Split('/');
            if (string.IsNullOrEmpty(application) && paths.Length >= 2) application = TextUtility.DecodeUrl(paths[1]);
            if (string.IsNullOrEmpty(function) && paths.Length >= 3) function = TextUtility.DecodeUrl(paths[2]);

            // 修正内容。
            application = TextUtility.Trim(application);
            function = TextUtility.Trim(function);
            random = TextUtility.Trim(random);
            ticket = TextUtility.Trim(ticket);
            session = TextUtility.Trim(session);
            page = TextUtility.Trim(page);

            // 设置请求：回传。
            request.Application = application;
            request.Function = function;
            request.Random = random;

            // 设置请求：不回传。
            request.Ticket = ticket;
            request.Session = session;
            request.Page = page;

            return request;
        }

        #endregion

        #region Response

        static StringPairs PrepareHeaders(ApiOptions options, ApiResponse response)
        {
            var merged = new StringPairs();
            if (options != null)
            {
                // 跨域访问。
                if (options.WithAccessControl)
                {
                    merged.Add("Access-Control-Allow-Headers", "Content-Type");
                    merged.Add("Access-Control-Allow-Methods", "GET, POST, OPTIONS");
                    merged.Add("Access-Control-Allow-Origin", "*");

                    var maxage = options.AccessControlMaxAge;
                    if (maxage > 0) merged.Add("Access-Control-Max-Age", maxage.ToString());
                }

                // Content-Type 检查。
                if (options.WithContentTypeOptions || options.Default != null)
                {
                    merged.Add("X-Content-Type-Options", "nosniff");
                }

                // 用于客户端，当前页面使用 HTTPS 时，将资源升级为 HTTPS。
                if (options.UpgradeHttps)
                {
                    merged.Add("Content-Security-Policy", "upgrade-insecure-requests");
                }
            }
            if (response != null)
            {
                // Cookies。
                var setCookie = SetCookie(response.Cookies);
                if (!string.IsNullOrEmpty(setCookie))
                {
                    merged.Add("Set-Cookie", setCookie);
                }

                // 自定义头。
                var headers = response.Headers;
                if (headers != null)
                {
                    foreach (var header in headers)
                    {
                        var key = TextUtility.Trim(header.Key);
                        if (string.IsNullOrEmpty(key)) continue;
                        var value = header.Value;
                        if (string.IsNullOrEmpty(value)) continue;
                        merged.Add(key, value);
                    }
                }
            }
            return merged;
        }

        internal static string ExportJson(ApiResponse response, ApiOptions options)
        {
            if (response == null) return "{}";
            if (string.IsNullOrEmpty(response.Status)) response.Status = "ok";

            var json = Json.NewObject();

            // 执行时间。
            if (options.WithClock)
            {
                json.SetProperty("clock", ClockUtility.Lucid(DateTime.Now));
            }

            // 持续时间。
            if (options.WithDuration)
            {
                json.SetProperty("duration", response.Duration);
            }

            // 随机值。
            var random = response.Random;
            if (!string.IsNullOrEmpty(random)) json.SetProperty("random", random);

            // 调用。
            if (options.WithTarget)
            {
                json.SetProperty("application", response.Application);
                json.SetProperty("function", response.Function);
            }

            // 状态。
            json.SetProperty("status", (TextUtility.IsBlank(response.Status) ? TextUtility.Empty : response.Status.ToLower()));
            if (!string.IsNullOrEmpty(response.Message)) json.SetProperty("message", response.Message);

            // 用户数据。
            if (response.Message == "exception" && !options.WithException) json.SetProperty("data");
            else json.SetProperty("data", response.Data);

            var indented = response.Indented || options.JsonIndent;
            var text = json.ToString(indented);
            return text;
        }

        internal static void Output(ApiProvider provider, ApiOptions options, string type, byte[] bytes)
        {
            var preWrite = provider.PreWrite();
            if (!string.IsNullOrEmpty(preWrite)) return;

            var headers = PrepareHeaders(options, null);
            foreach (var header in headers) provider.SetHeader(header.Key, header.Value);

            provider.SetCache(0);
            provider.SetContentType(string.IsNullOrEmpty(type) ? "application/octet-stream" : type);

            var length = bytes == null ? 0 : bytes.Length;
            provider.SetContentLength(length);
            if (length > 0) provider.ResponseBody().Write(bytes);
        }

        internal static void Output(ApiProvider provider, ApiOptions options, ApiResponse response, ApiRequest request, HttpMethod method)
        {
            var preWrite = provider.PreWrite();
            if (!string.IsNullOrEmpty(preWrite)) return;

            // 设置头。
            var headers = PrepareHeaders(options, null);
            foreach (var header in headers) provider.SetHeader(header.Key, header.Value);

            var model = response.Model;
            if (model != null)
            {
                ApiUtility.Initialize(model, request, response, options, provider);
                try { model.Output(); } catch { }
                RuntimeUtility.Dispose(model);
                return;
            }

            var json = TextUtility.Bytes(ExportJson(response, options));
            provider.SetCache(0);
            provider.SetContentType("text/json; charset=utf-8");
            provider.SetContentLength(json.Length);
            var stream = provider.ResponseBody();
            if (stream != null && stream.CanWrite) stream.Write(json);
        }

        #endregion

    }

}