public static class EntityFrameworkCoreExtension
{
private static DbCommand CreateCommand(DatabaseFacade facade, string sql, out DbConnection connection, params object[] parameters)
{
var conn = facade.GetDbConnection();
connection = conn;
conn.Open();
var cmd = conn.CreateCommand();
cmd.CommandText = sql;
cmd.Parameters.AddRange(parameters);
return cmd;
}
public static DataTable SqlQuery(this DatabaseFacade facade, string sql, params object[] parameters)
{
var command = CreateCommand(facade, sql, out DbConnection conn, parameters);
var reader = command.ExecuteReader();
var dt = new DataTable();
dt.Load(reader);
reader.Close();
conn.Close();
return dt;
}
public static List<T> SqlQuery<T>(this DatabaseFacade facade, string sql, params object[] parameters) where T : class, new()
{
var dt = SqlQuery(facade, sql, parameters);
return dt.ToList<T>();
}
public static List<T> ToList<T>(this DataTable dt) where T : class, new()
{
var propertyInfos = typeof(T).GetProperties();
var list = new List<T>();
foreach (DataRow row in dt.Rows)
{
var t = new T();
foreach (PropertyInfo p in propertyInfos)
{
if (dt.Columns.IndexOf(p.Name) != -1 && row[p.Name] != DBNull.Value)
{
p.SetValue(t, row[p.Name], null);
}
}
list.Add(t);
}
return list;
}
}调用示例：
var data = db.Database.SqlQuery<List<string>>("SELECT 'title' FROM `table` WHERE `id` = {0};", id);普通的 nginx http 反向代理 https 时是需要配置证书的，但我们又不可能由源域名的证书，所以要使用 nginx 的 stream 模块。普通的 nginx 反向代理属于第七层代理，而 stream 模块是第四层代理，通过转发的 tcp/ip 协议实现高功能，所以不需要证书。
我们这里以使用宝塔安装的 nginx 为例，其实其他系统也是类似，只要找到编译的 nginx 的源码目录就行了
编译前先将已经安装的 nginx 文件进行备份
通过 ps 命令查看 nginx 文件的路径。以下所有步骤都以自身 nginx 路径为准
# ps -elf | grep nginx
# cd /www/server/nginx/sbin/
# cp nginx nginx.bak然后查看当前 nginx 编译的参数
/www/server/nginx/sbin/nginx -V将 ./configure arguents：之后的内容复制到记事本备用（备注：我们这里其实使用的是 Tengine-2.3.1，所以下面的编译参数可能跟普通 nginx 不是很一样）
内容如下：
--user=www --group=www --prefix=/www/server/nginx --add-module=/www/server/nginx/src/ngx_devel_kit --with-openssl=/www/server/nginx/src/openssl --add-module=/www/server/nginx/src/ngx_cache_purge --add-module=/www/server/nginx/src/nginx-sticky-module --add-module=/www/server/nginx/src/lua_nginx_module --with-http_stub_status_module --with-http_ssl_module --with-http_v2_module --with-http_image_filter_module --with-http_gzip_static_module --with-http_gunzip_module --with-ipv6 --with-http_sub_module --with-http_flv_module --with-http_addition_module --with-http_realip_module --with-http_mp4_module --with-ld-opt=-Wl,-E --with-pcre=pcre-8.42 --with-cc-opt=-Wno-error --add-module=/www/server/nginx/src/ngx-pagespeed
进入 src 目录
cd /www/server/nginx/src我们在上面的内容中加入两个参数
./configure --user=www --group=www --prefix=/www/server/nginx --add-module=/www/server/nginx/src/ngx_devel_kit --with-openssl=/www/server/nginx/src/openssl --add-module=/www/server/nginx/src/ngx_cache_purge --add-module=/www/server/nginx/src/nginx-sticky-module --add-module=/www/server/nginx/src/lua_nginx_module --with-http_stub_status_module --with-http_ssl_module --with-http_v2_module --with-http_image_filter_module --with-http_gzip_static_module --with-http_gunzip_module --with-ipv6 --with-http_sub_module --with-http_flv_module --with-http_addition_module --with-http_realip_module --with-http_mp4_module --with-ld-opt=-Wl,-E --with-pcre=pcre-8.42 --with-cc-opt=-Wno-error --add-module=/www/server/nginx/src/ngx-pagespeed --with-stream --with-stream_ssl_preread_module
并执行它
然后
make && make install重启 nginx
service nginx restartnginx -V 看看模块是不是加载了
新建个站点，配置反向代理
卸载
使用 nginx.bak 文件替换掉自编译的 nginx 文件，替换后重启 nginx。
using Microsoft.AspNetCore.Mvc;
using Microsoft.EntityFrameworkCore;
namespace xxx.xxx.xxx.Controllers
{
public class DiscuzTinyintViewerController : Controller
{
public IActionResult Index()
{
using var context = new Data.xxx.xxxContext();
var conn = context.Database.GetDbConnection();
conn.Open();
using var cmd = conn.CreateCommand();
cmd.CommandText = "SELECT `TABLE_NAME` FROM information_schema.TABLES WHERE TABLE_SCHEMA = DATABASE();";
Dictionary<string, List<FieldType>?> tables = new();
using var r = cmd.ExecuteReader();
while (r.Read())
{
tables.Add((string)r["TABLE_NAME"], null);
}
conn.Close();
foreach (var table in tables)
{
var conn2 = context.Database.GetDbConnection();
conn2.Open();
using var cmd2 = conn2.CreateCommand();
cmd2.CommandText = "DESCRIBE " + table.Key;
using var r2 = cmd2.ExecuteReader();
List<FieldType> fields = new();
while (r2.Read())
{
if (((string)r2[1]).Contains("tinyint(1)"))
{
fields.Add(new()
{
Field = (string)r2[0],
Type = (string)r2[1],
Null = (string)r2[2],
});
}
}
conn2.Close();
tables[table.Key] = fields;
}
foreach (var table in tables)
{
foreach (var f in table.Value)
{
var conn3 = context.Database.GetDbConnection();
conn3.Open();
using var cmd3 = conn3.CreateCommand();
cmd3.CommandText = $"SELECT {f.Field} as F, COUNT({f.Field}) as C FROM {table.Key} GROUP BY {f.Field}";
using var r3 = cmd3.ExecuteReader();
List<FieldType.ValueCount> vs = new();
while (r3.Read())
{
vs.Add(new() { Value = Convert.ToString(r3["F"]), Count = Convert.ToInt32(r3["C"]) });
}
conn3.Close();
f.groupedValuesCount = vs;
}
}
return Json(tables.Where(c => c.Value != null && c.Value.Count > 0));
}
private class FieldType
{
public string Field { get; set; }
public string Type { get; set; }
public string Null { get; set; }
public List<ValueCount> groupedValuesCount { get; set; }
public class ValueCount
{
public string Value { get; set; }
public int Count { get; set; }
}
public string RecommendedType
{
get
{
if (groupedValuesCount == null || groupedValuesCount.Count < 2)
{
return "无建议";
}
else if (groupedValuesCount.Count == 2 && groupedValuesCount.Any(c => c.Value == "0") && groupedValuesCount.Any(c => c.Value == "1"))
{
return "bool" + (Null == "YES" ? "?" : "");
}
else
{
return "sbyte" + (Null == "YES" ? "?" : "");
}
}
}
}
}
}[{
"key": "pre_forum_post",
"value": [{
"field": "first",
"type": "tinyint(1)",
"null": "NO",
"groupedValuesCount": [{
"value": "0",
"count": 1395501
}, {
"value": "1",
"count": 179216
}],
"recommendedType": "bool"
}, {
"field": "invisible",
"type": "tinyint(1)",
"null": "NO",
"groupedValuesCount": [{
"value": "-5",
"count": 9457
}, {
"value": "-3",
"count": 1412
}, {
"value": "-2",
"count": 1122
}, {
"value": "-1",
"count": 402415
}, {
"value": "0",
"count": 1160308
}, {
"value": "1",
"count": 3
}],
"recommendedType": "sbyte"
}, {
"field": "anonymous",
"type": "tinyint(1)",
"null": "NO",
"groupedValuesCount": [{
"value": "0",
"count": 1574690
}, {
"value": "1",
"count": 27
}],
"recommendedType": "bool"
}, {
"field": "usesig",
"type": "tinyint(1)",
"null": "NO",
"groupedValuesCount": [{
"value": "0",
"count": 162487
}, {
"value": "1",
"count": 1412230
}],
"recommendedType": "bool"
}, {
"field": "htmlon",
"type": "tinyint(1)",
"null": "NO",
"groupedValuesCount": [{
"value": "0",
"count": 1574622
}, {
"value": "1",
"count": 95
}],
"recommendedType": "bool"
}, {
"field": "bbcodeoff",
"type": "tinyint(1)",
"null": "NO",
"groupedValuesCount": [{
"value": "-1",
"count": 935448
}, {
"value": "0",
"count": 639229
}, {
"value": "1",
"count": 40
}],
"recommendedType": "sbyte"
}, {
"field": "smileyoff",
"type": "tinyint(1)",
"null": "NO",
"groupedValuesCount": [{
"value": "-1",
"count": 1359482
}, {
"value": "0",
"count": 215186
}, {
"value": "1",
"count": 49
}],
"recommendedType": "sbyte"
}, {
"field": "parseurloff",
"type": "tinyint(1)",
"null": "NO",
"groupedValuesCount": [{
"value": "0",
"count": 1572844
}, {
"value": "1",
"count": 1873
}],
"recommendedType": "bool"
}, {
"field": "attachment",
"type": "tinyint(1)",
"null": "NO",
"groupedValuesCount": [{
"value": "0",
"count": 1535635
}, {
"value": "1",
"count": 2485
}, {
"value": "2",
"count": 36597
}],
"recommendedType": "sbyte"
}, {
"field": "comment",
"type": "tinyint(1)",
"null": "NO",
"groupedValuesCount": [{
"value": "0",
"count": 1569146
}, {
"value": "1",
"count": 5571
}],
"recommendedType": "bool"
}]
}]
Regex.Escape(String) 方法：
通过替换为转义码来转义最小的字符集（\、*、+、?、|、{、[、(、)、^、$、.、# 和空白）。 这将指示正则表达式引擎按原义解释这些字符而不是解释为元字符。
示例：
string str = @"123\c\d\e";
string r1 = @"\d";
string r2 = Regex.Escape(r1);
return Json(new
{
m1 = Regex.Matches(str, r1).Select(c => c.Value),
m2 = Regex.Matches(str, r2).Select(c => c.Value)
});结果：
{
"m1":[
"1",
"2",
"3"
],
"m2":[
"\\d"
]
}一般地，我们使用通配符 a*c 在字符串 abcd 中查找：
string s = @"abcd";
string w = @"a*c";
string r = Regex.Escape(w).Replace(@"\*", @".*?").Replace(@"\?", @".?");
return Content(Regex.Match(s, r).Value);结果：
abc同理，使用通配符 \d*\f 在字符串 \a\b\c\d\e\f 中查找：
string s = @"\a\b\c\d\e\f";
string w = @"\d*\f";
string r = Regex.Escape(w).Replace(@"\*", @".*?").Replace(@"\?", @".?");
return Content(Regex.Match(s, r).Value);结果：
\d\e\f测试在长度为 403 的字符串中查找，特意匹配最后几个字符：
string a = "";
for (int i = 0; i < 100; i++) { a += "aBcD"; }
a += "xYz";
string b = "xyz"; // 特意匹配最后几个字符
Stopwatch sw1 = Stopwatch.StartNew();
bool? r1 = null;
for (int i = 0; i < 10000; i++) { r1 = a.IndexOf(b) >= 0; }
sw1.Stop();
Stopwatch sw2 = Stopwatch.StartNew();
bool? r2 = null;
for (int i = 0; i < 10000; i++) { r2 = a.Contains(b); }
sw2.Stop();
Stopwatch sw3 = Stopwatch.StartNew();
bool? r3 = null;
for (int i = 0; i < 10000; i++) { r3 = a.ToUpper().Contains(b.ToUpper()); }
sw3.Stop();
Stopwatch sw4 = Stopwatch.StartNew();
bool? r4 = null;
for (int i = 0; i < 10000; i++) { r4 = a.ToLower().Contains(b.ToLower()); }
sw4.Stop();
Stopwatch sw5 = Stopwatch.StartNew();
bool? r5 = null;
for (int i = 0; i < 10000; i++) { r5 = a.Contains(b, StringComparison.OrdinalIgnoreCase); }
sw5.Stop();
Stopwatch sw6 = Stopwatch.StartNew();
bool? r6 = null;
for (int i = 0; i < 10000; i++) { r6 = a.Contains(b, StringComparison.CurrentCultureIgnoreCase); }
sw6.Stop();
Stopwatch sw7 = Stopwatch.StartNew();
bool? r7 = null;
for (int i = 0; i < 10000; i++) { r7 = Regex.IsMatch(a, b); }
sw7.Stop();
Stopwatch sw8 = Stopwatch.StartNew();
bool? r8 = null;
for (int i = 0; i < 10000; i++) { r8 = Regex.IsMatch(a, b, RegexOptions.IgnoreCase); }
sw8.Stop();
return Json(new
{
IndexOf_________________ = sw1.Elapsed + " " + r1,
Contains________________ = sw2.Elapsed + " " + r2,
ToUpper_________________ = sw3.Elapsed + " " + r3,
ToLower_________________ = sw4.Elapsed + " " + r4,
OrdinalIgnoreCase_______ = sw5.Elapsed + " " + r5,
CurrentCultureIgnoreCase = sw6.Elapsed + " " + r6,
IsMatch_________________ = sw7.Elapsed + " " + r7,
IsMatchIgnoreCase_______ = sw8.Elapsed + " " + r8,
});结果参考：
{
"indexOf_________________": "00:00:00.1455812 False",
"contains________________": "00:00:00.0003791 False",
"toUpper_________________": "00:00:00.0038182 True",
"toLower_________________": "00:00:00.0026113 True",
"ordinalIgnoreCase_______": "00:00:00.0096550 True",
"currentCultureIgnoreCase": "00:00:00.1596517 True",
"isMatch_________________": "00:00:00.0053627 False",
"isMatchIgnoreCase_______": "00:00:00.0084132 True"
}SelectMany() 的作用与 GroupBy() 相反，例：
List<List<int>> list = new() { new() { 1, 2, 3 }, new() { 4, 5, 6 } };
return Json(list.SelectMany(c => c));输出：
[1,2,3,4,5,6]
测试表数据量 152 万条，测试跳过 100 万取 10 条。
测试一：直接使用 limit 跳过 1000000 取 10，耗时 2.4s；
SELECT *
FROM `pre_forum_post`
ORDER BY `pid`
LIMIT 1000000, 10
> OK
> 时间: 2.394s测试二：先使用 limit 跳过 1000000 取 1，再使用配合 where 条件，使用 limit 取 10，耗时 0.2s。
SELECT *
FROM `pre_forum_post`
WHERE `pid` >= (
SELECT `pid`
FROM `pre_forum_post`
ORDER BY `pid`
LIMIT 1000000, 1
)
ORDER BY `pid`
LIMIT 10
> OK
> 时间: 0.207s两次测试耗时相差约 10 倍。测试取 100 条或取 1 条，耗时都相差约 10 倍。
但若测试跳过条数较小时，测试一效率更高，因此应按照项目的实际需要选择适当的查询方法。
System.NotSupportedException: Serialization and deserialization of 'System.DateOnly' instances are not supported.
The unsupported member type is located on type 'System.Nullable`1[System.DateOnly]'.
解决方法：
https://www.nuget.org/packages/DateOnlyTimeOnly.AspNet/
builder.Services
.AddControllers(options => options.UseDateOnlyTimeOnlyStringConverters())
.AddJsonOptions(options => options.UseDateOnlyTimeOnlyStringConverters());POST
axios.post('AjaxCases', {
following: true,
success: null,
page: 1,
}).then(function (response) {
console.log(response.data)
}).catch(function (error) {
console.log(error.response.data);
});[HttpPost]
public IActionResult AjaxCases([FromBody] AjaxCasesRequestModel req)
{
bool? following = req.following;
bool? success = req.success;
int page = req.page;
}GET
axios.get('AjaxCase', {
params: {
int: 123,
}
}).then(function (response) {
console.log(response.data)
}).catch(function (error) {
console.log(error.response.data);
});[HttpGet]
public IActionResult AjaxCases([FromQuery] int id)
{
}DELETE
格式与 GET 类似
* 若服务端获取参数值为 null，可能的情况如下：
请检查相关枚举类型是否已设置 [JsonConverter] 属性，参：C# 枚举（enum）用法笔记，且传入的值不能为空字符串，可以传入 null 值，并将服务端 enum 类型改为可空。可以以 string 方式接收参数后再进行转换。
模型中属性名称不能重复（大小写不同也不行）。
布尔型属性值必须传递布尔型值，即在 JS 中，字符串 "true" 应 JSON.parse("true") 为 true 后再回传给服务端。
第一步：下载安装 OBS Studio 插件：Advanced Scene Switcher
第二步：在 OBS 中预先添加两个可供直播的场景
第三步：在 OBS 菜单中打开：工具 - 高级场景切换器
切换器的功能十分强大，这里实现一种简单的随机场景切换。
切换到“随机场景列表”选项卡，点左下角“+”按钮添加现有场景，并设置转场特效和保留时间（单位“秒”）
切换到“通用”选项卡，点击“启动”
现在可以在主窗口中看到场景切换效果了。
如果设置特殊的转场特效，在主窗口的“转场特效”中添加后，可以“高级场景切换器”中选用。
