ASP.NET C# 执行.exe进程完成后触发页面重载的实现问题

我正在开发一款通过Web GUI配置软件组件的应用，其中一个配置模块需要调用可执行程序选择SFTP文件夹，选中的路径会和其他参数共同存入JSON文件，最终回显到表单输入字段中。

前端cshtml代码 #

<button class="btn btn-primary" onclick="browseSftp()">Select SFTP folder</button>

<script>
function browseSftp() {
    window.$.ajax({
        type: "POST",
        url: "/BackupConfiguration?handler=BrowseSftp",
        contentType: "application/json; charset=utf-8",
        beforeSend: function (xhr) {
            xhr.setRequestHeader("XSRF-TOKEN",
                window.$('input:hidden[name="__RequestVerificationToken"]').val());
        },
        data: JSON.stringify({
            autoBackup: $('input[name="FormData.autoBackup"]:checked').val(),
            backupTime: $('#FormData_backupTime').val(),
            keepAllBackups: $('input[name="FormData.keepAllBackups"]:checked').val(),
            backupsKept: $('#FormData_backupsKept').val(),
            hostName: $('#FormData_hostName').val(),
            hostKey: $('#FormData_hostKey').val(),
            port: $('#FormData_port').val(),
            username: $('#FormData_username').val(),
            password: $('#FormData_password').val(),
            remoteFolder: $('#FormData_remoteFolder').val(),
            localFolder: $('#FormData_localFolder').val(),
            isLocal: $('input[name="FormData.isLocal"]:checked').val(),
        }),
        success: function (response) {
            alert("success");
        }
    });
};
</script>

后端cshtml.cs接口代码 #

public void OnPostBrowseSftp([FromBody] FormData formData)
{
    //string[] args = { FormData.autoBackup, FormData.backupTime, FormData.keepAllBackups, FormData.backupsKept, FormData.hostName, FormData.hostKey, FormData.port, FormData.username, FormData.password, FormData.remoteFolder, FormData.localFolder, "TRUE" };

    string[] args = {FormData.hostName,  FormData.username, FormData.password};
    if(formData.autoBackup == null)
    {
        formData.autoBackup = "false";
    }
    if(formData.keepAllBackups == null)
    {
        formData.keepAllBackups = "false";
    }

   
   var process =  System.Diagnostics.Process.Start(_browseSftpScript, formData.hostName + " " + formData.username + " " + formData.password + " " + formData.autoBackup + " " + formData.backupTime + " " + formData.keepAllBackups + " " + formData.backupsKept + " " + formData.port + " " + formData.isLocal + " "  + _jsonPath);
       process.WaitForExit();
       Response.Redirect("/backupConfiguration");
}

OnGet页面初始化代码 #

public void OnGet()
{
    if (HttpContext.Session.GetString(SettingName) == null || HttpContext.Session.GetString(SettingName) != "AlreadyLoaded")
    {
        HttpContext.Session.SetString(SettingName, "AlreadyLoaded");
        if (System.IO.File.Exists(_systemSettingJsonPath))
        {
            FormData = SettingsService.GetData<FormData>(_systemSettingJsonPath);
            SettingsService.SaveData(FormData, _jsonPath);
        }
        else
        {
            FormData = SettingsService.GetData<FormData>(_jsonPath);
        }
    }
    else
    {
        FormData = SettingsService.GetData<FormData>(_jsonPath);
    }

}

问题现象 #

正常来说OnGet方法会重新初始化页面、填充表单字段，但当前没有生效，只有手动跳转到其他页面再返回时才会加载最新数据。查看日志后推测原因是OnGet方法在BrowseSftp请求处理完成前就被调用：

2021-11-25 17:31:22.922 +01:00 [Microsoft.AspNetCore.Routing.EndpointMiddleware] [INF] Executed endpoint '/BackupConfiguration'
2021-11-25 17:31:22.922 +01:00 [Microsoft.AspNetCore.Hosting.Diagnostics] [INF] Request finished HTTP/1.1 POST http://localhost:5000/BackupConfiguration?handler=BrowseSftp application/json;+charset=UTF-8 228 - 200 - text/html;+charset=utf-8 705431.7372ms

原本预期process.WaitForExit();执行完再跳转页面的逻辑未生效，最终目标是在.exe进程执行完毕后正常触发页面重载。

你的问题核心有两个，依次修改即可：

1. 后端Response.Redirect对AJAX请求无效
   你用AJAX发送POST请求时，后端返回的302跳转指令只会被AJAX异步处理，浏览器不会主动刷新当前页面，跳转后的页面内容只会作为响应返回给前端JS的success回调，所以你看不到页面刷新。
   解决方法：不要在后端做跳转，改成在前端AJAX的success回调里执行页面刷新，修改前端JS的success逻辑：

success: function (response) {
    // 进程执行完成后主动刷新当前页
    window.location.reload();
}

同时删掉后端OnPostBrowseSftp里的Response.Redirect("/backupConfiguration");代码即可。

2. OnGet方法的Session判断逻辑冗余
   你在OnGet里设置了AlreadyLoaded的Session标识，只要Session没过期，后续刷新页面只会走else分支，虽然你else分支是读取最新的_jsonPath，不会影响配置读取，但如果有系统配置更新的场景会导致无法同步，不需要该逻辑可以直接删除Session判断，或者在调用完SFTP选择程序后主动清空这个Session标识。

另外补充一个优化点：你拼接进程启动参数的时候直接用空格拼接，如果参数里有空格会导致参数解析错误，建议给每个参数加上双引号包裹，避免参数解析异常。

内容的提问来源于stack exchange，提问作者Jukilo