Masuit.Tools/Masuit.Tools.AspNetCore/ModelBinder/FromBodyOrDefaultModelBinder.cs

using System.Collections;
using System.Net.Mime;
using System.Reflection;
using System.Xml.Linq;
using Masuit.Tools.Systems;
using Microsoft.AspNetCore.Mvc.ModelBinding;
using Microsoft.Extensions.DependencyInjection;
using Microsoft.Extensions.Logging;
using Microsoft.Extensions.Primitives;
using Newtonsoft.Json.Linq;

namespace Masuit.Tools.AspNetCore.ModelBinder;

public class FromBodyOrDefaultModelBinder(ILogger<FromBodyOrDefaultModelBinder> logger) : IModelBinder
{
    private static readonly List<BindType> BindTypes =
    [
        BindType.Query,
        BindType.Body,
        BindType.Header,
        BindType.Form,
        BindType.Cookie,
        BindType.Route
    ];

    public Task BindModelAsync(ModelBindingContext bindingContext)
    {
        var context = bindingContext.HttpContext;
        var attr = bindingContext.GetAttribute<FromBodyOrDefaultAttribute>();
        var field = attr?.FieldName ?? bindingContext.FieldName;
        var modelType = bindingContext.ModelType;
        object value = null;
        Exception exception = null;
        if (attr != null)
        {
            if (modelType.IsSimpleType() || modelType.IsSimpleArrayType() || modelType.IsSimpleListType())
            {
                if (attr.Type == BindType.Default)
                {
                    foreach (var type in BindTypes)
                    {
                        value = GetBindingValue(bindingContext, type, field, modelType);
                        if (value != null)
                        {
                            break;
                        }
                    }
                }
                else
                {
                    foreach (var type in attr.Type.Split())
                    {
                        value = GetBindingValue(bindingContext, type, field, modelType);
                        if (value != null)
                        {
                            break;
                        }
                    }
                }
            }
            else
            {
                if (bindingContext.HttpContext.Items.TryGetValue("BodyOrDefaultModelBinder@JsonBody", out var obj) && obj is JObject json)
                {
                    if (modelType.IsArray || modelType.IsGenericType && modelType.GenericTypeArguments.Length == 1)
                    {
                        if (json.TryGetValue(field, StringComparison.OrdinalIgnoreCase, out var jtoken))
                        {
                            if (jtoken.Type is JTokenType.String)
                            {
                                jtoken.Value<string>().TryConvertTo(modelType, out value);
                            }
                            else
                            {
                                value = jtoken.ToObject(modelType);
                            }
                        }
                        else
                        {
                            logger.LogWarning($"TraceIdentifier：{context.TraceIdentifier}，BodyOrDefaultModelBinder从{json}中获取{field}失败！");
                        }
                    }
                    else
                    {
                        // 可能是 字典或者实体 类型,尝试将modeltype 当初整个请求参数对象
                        try
                        {
                            value = json.ToObject(modelType);
                        }
                        catch (Exception e)
                        {
                            logger.LogError(e, e.Message, json.ToString());
                            exception = e;
                        }
                    }
                }

                if (value == null)
                {
                    var (requestData, keys) = GetRequestData(bindingContext, modelType);
                    if (keys.Any())
                    {
                        var instance = Activator.CreateInstance(modelType);
                        switch (requestData)
                        {
                            case IEnumerable<KeyValuePair<string, StringValues>> stringValues:
                                {
                                    foreach (var item in stringValues)
                                    {
                                        var property = modelType.GetProperty(item.Key, BindingFlags.IgnoreCase | BindingFlags.Public | BindingFlags.Instance);
                                        if (property != null)
                                        {
                                            property.SetValue(instance, item.Value.ConvertObject(property.PropertyType));
                                        }
                                    }

                                    break;
                                }
                            case IEnumerable<KeyValuePair<string, string>> strs:
                                {
                                    //处理Cookie
                                    foreach (var item in strs)
                                    {
                                        var property = modelType.GetProperty(item.Key, BindingFlags.IgnoreCase | BindingFlags.Public | BindingFlags.Instance);
                                        if (property != null)
                                        {
                                            property.SetValue(instance, item.Value.ConvertObject(property.PropertyType));
                                        }
                                    }

                                    break;
                                }
                            case IEnumerable<KeyValuePair<string, object>> objects:
                                {
                                    //处理路由
                                    foreach (var item in objects)
                                    {
                                        var property = modelType.GetProperty(item.Key, BindingFlags.IgnoreCase | BindingFlags.Public | BindingFlags.Instance);
                                        if (property != null)
                                        {
                                            property.SetValue(instance, item.Value.ConvertObject(property.PropertyType));
                                        }
                                    }

                                    break;
                                }
                        }

                        value = instance;
                    }
                }
            }

            if (value == null && attr.DefaultValue != null)
            {
                value = attr.DefaultValue.ChangeType(modelType);
            }
        }

        if (value != null)
        {
            bindingContext.Result = ModelBindingResult.Success(value);
        }

        if (exception != null)
        {
            throw exception;
        }

        return Task.CompletedTask;
    }

    private static (IEnumerable data, List<string> keys) GetRequestData(ModelBindingContext bindingContext, Type type)
    {
        var request = bindingContext.HttpContext.Request;
        var props = type.GetProperties().Select(t => t.Name).ToList();
        var query = props.Except(request.Query.Keys, StringComparer.OrdinalIgnoreCase).ToList();
        var headers = props.Except(request.Headers.Keys, StringComparer.OrdinalIgnoreCase).ToList();
        var cookies = props.Except(request.Cookies.Keys, StringComparer.OrdinalIgnoreCase).ToList();
        var routes = props.Except(bindingContext.ActionContext.RouteData.Values.Keys, StringComparer.OrdinalIgnoreCase).ToList();
        var list = new List<KeyValuePair<List<string>, IEnumerable>>()
        {
            new(query, request.Query),
            new(headers, request.Headers),
            new(cookies, request.Cookies),
            new(routes, bindingContext.ActionContext.RouteData.Values),
        };

        if (request.HasFormContentType && request.Form.Count > 0)
        {
            var forms = props.Except(request.Form.Keys, StringComparer.OrdinalIgnoreCase).ToList();
            list.Add(new KeyValuePair<List<string>, IEnumerable>(forms, request.Form));
        }

        var kv = list.OrderBy(t => t.Key.Count).FirstOrDefault();
        return (kv.Value, props.Except(kv.Key).ToList());
    }

    /// <summary>
    /// 获取要绑定的值
    /// </summary>
    /// <param name="bindingContext"></param>
    /// <param name="bindType"></param>
    /// <param name="fieldName"></param>
    /// <param name="modelType"></param>
    private object GetBindingValue(ModelBindingContext bindingContext, BindType bindType, string fieldName, Type modelType)
    {
        var context = bindingContext.HttpContext;
        var mediaType = string.Empty;
        if (!string.IsNullOrWhiteSpace(context.Request.ContentType))
        {
            try
            {
                var contentType = new ContentType(context.Request.ContentType);
                mediaType = contentType.MediaType.ToLower();
            }
            catch (Exception ex)
            {
                logger.LogError(ex, "Parsing contentType failed:" + context.Request.ContentType);
                mediaType = "multipart/form-data";
            }
        }

        object targetValue = null;
        switch (bindType)
        {
            case BindType.Body:
                switch (mediaType)
                {
                    case "application/json":
                        {
                            if (bindingContext.HttpContext.Items.TryGetValue("BodyOrDefaultModelBinder@JsonBody", out var obj) && obj is JObject json && json.TryGetValue(fieldName, StringComparison.OrdinalIgnoreCase, out var values))
                            {
                                targetValue = values.ConvertObject(modelType);
                            }
                        }

                        break;

                    case "application/xml":
                        {
                            if (bindingContext.HttpContext.Items.TryGetValue("BodyOrDefaultModelBinder@XmlBody", out var obj) && obj is XDocument xml)
                            {
                                var xmlElt = xml.Element(fieldName);
                                if (xmlElt != null)
                                {
                                    targetValue = xmlElt.Value.ConvertObject(modelType);
                                }
                            }

                            break;
                        }
                }

                break;

            case BindType.Query:
                {
                    if (context.Request.Query is { Count: > 0 } && context.Request.Query.TryGetValue(fieldName, out var values))
                    {
                        targetValue = values.ConvertObject(modelType);
                    }
                }

                break;

            case BindType.Form:
                {
                    if (context.Request is { HasFormContentType: true, Form.Count: > 0 } && context.Request.Form.TryGetValue(fieldName, out var values))
                    {
                        targetValue = values.ConvertObject(modelType);
                    }
                }

                break;

            case BindType.Header:
                {
                    if (context.Request.Headers is { Count: > 0 } && context.Request.Headers.TryGetValue(fieldName, out var values))
                    {
                        targetValue = values.ConvertObject(modelType);
                    }
                }

                break;

            case BindType.Cookie:
                {
                    if (context.Request.Cookies is { Count: > 0 } && context.Request.Cookies.TryGetValue(fieldName, out var values))
                    {
                        targetValue = values.ConvertObject(modelType);
                    }
                }

                break;

            case BindType.Route:
                {
                    if (bindingContext.ActionContext.RouteData.Values is { Count: > 0 } && bindingContext.ActionContext.RouteData.Values.TryGetValue(fieldName, out var values))
                    {
                        targetValue = values.ConvertObject(modelType);
                    }
                }

                break;

            case BindType.Services:
                targetValue = bindingContext.ActionContext.HttpContext.RequestServices.GetRequiredService(modelType);
                break;
        }

        return targetValue;
    }
}