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Steps to install windows service

  1. Create a start.bat file with content npm start
  2. Download nssm
  3. Extract it and go to nssm/win64 folder
  4. Type nssm install service-name from command prompt
  5. Select start.bat as Application Path, you could also add your startup Arguments here
  6. Start service with nssm start service-name
  7. You could find it already registered as windows service :)

NSSM commands reference

You could type nssm anytime to see this document

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M:\nssm-2.24\win64>nssm
NSSM: The non-sucking service manager
Version 2.24 64-bit, 2014-08-31
Usage: nssm <option> [<args> ...]

To show service installation GUI:

        nssm install [<servicename>]

To install a service without confirmation:

        nssm install <servicename> <app> [<args> ...]

To show service editing GUI:

        nssm edit <servicename>

To retrieve or edit service parameters directly:

        nssm get <servicename> <parameter> [<subparameter>]

        nssm set <servicename> <parameter> [<subparameter>] <value>

        nssm reset <servicename> <parameter> [<subparameter>]

To show service removal GUI:

        nssm remove [<servicename>]

To remove a service without confirmation:

        nssm remove <servicename> confirm

To manage a service:

        nssm start <servicename>

        nssm stop <servicename>

        nssm restart <servicename>

        nssm status <servicename>

        nssm rotate <servicename>

Reference

http://nssm.cc

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ECONNRESET when making thousands requests

In situation doing thousands of http requests, it is easy to get error ECONNRESET, for example :

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require('isomorphic-fetch');

const promises = []
for(var i=0; i<10000; i++){
    promises.push(fetch('http://example.com/'+i));
}

const results = await Promise.all(promises)
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-- Get current datetime
GETDATE()

-- Get year of datetime
YEAR(GETDATE())

-- Get difference between dates
DATEDIFF(dateformat, startdate, enddate)

-- Subtract date, e.g.: DATEADD(HOUR, -11, GETDATE())
DATEADD(Unit of time, value, date)

-- Avalable Unit of time value
NANOSECOND, MICROSECOND, MILLISECOND, SECOND, MINUTE, HOUR, WEEKDAY, WEEK, DAY, DAYOFYEAR, MONTH, QUARTER, YEAR

-- Between
select * from User where CreatedDate between '2016-09-26' and '2016-09-27'

-- Order by
select * from User order by column desc

-- Group by
select UserCode, Count(*) from User group by UserCode

-- Select top 10
SELECT TOP (10) * from User

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Today When I connect to Windows through Remote Desktop Viewer got error connecting to host prompt.
After searching the solution is to remove the server I’m having issue in $home/.freerdp/known_hosts and reconnecting again.

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[[email protected] ~]$ vi ~/.freerdp/known_hosts
# In Vim, remove the line start with server ip you are connecting to by `dd`, and `:wq` to save the file.

Reference: https://superuser.com/questions/834447/vinagre-remote-desktop-viewer-for-gnome-isnt-working-out-of-box

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PostAsync

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static readonly HttpClient Client = new HttpClient();
public async Task<T> PostAsync<T>(string url, object data) where T : class, new()
{
    try
    {
        string content = JsonConvert.SerializeObject(data);
        var buffer = Encoding.UTF8.GetBytes(content);
        var byteContent = new ByteArrayContent(buffer);
        byteContent.Headers.ContentType = new MediaTypeHeaderValue("application/json");
        var response = await Client.PostAsync(url, byteContent).ConfigureAwait(false);
        string result = await response.Content.ReadAsStringAsync();
        if (response.StatusCode != HttpStatusCode.OK)
        {
            logger.Error($"GetAsync End, url:{url}, HttpStatusCode:{response.StatusCode}, result:{result}");
            return new T();
        }
        logger.Info($"GetAsync End, url:{url}, result:{result}");
        return JsonConvert.DeserializeObject<T>(result);
    }
    catch (WebException ex)
    {
        if (ex.Response != null)
        {
            string responseContent = new StreamReader(ex.Response.GetResponseStream()).ReadToEnd();
            throw new System.Exception($"response :{responseContent}", ex);
        }
        throw;
    }
}

GetAsync

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static readonly HttpClient Client = new HttpClient();
public async Task<string> GetAsync(string url, object data)
{
    try
    {
        string requestUrl = $"{url}?{GetQueryString(data)}";
        logger.Info($"GetAsync Start, requestUrl:{requestUrl}");
        var response = await Client.GetAsync(requestUrl).ConfigureAwait(false);
        string result = await response.Content.ReadAsStringAsync();
        logger.Info($"GetAsync End, requestUrl:{requestUrl}, HttpStatusCode:{response.StatusCode}, result:{result}");
        return result;
    }
    catch (WebException ex)
    {
        if (ex.Response != null)
        {
            string responseContent = new StreamReader(ex.Response.GetResponseStream()).ReadToEnd();
            throw new Exception($"Response :{responseContent}", ex);
        }
        throw;
    }
}

private static string GetQueryString(object obj)
{
    var properties = from p in obj.GetType().GetProperties()
                        where p.GetValue(obj, null) != null
                        select p.Name + "=" + HttpUtility.UrlEncode(p.GetValue(obj, null).ToString());

    return String.Join("&", properties.ToArray());
}

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This sheet is to record abbreviation in my daily work as a software engineer.

Abbreviation Full name Explain
CDC Change data capture Use to sync one db data change to another db
MPLS Multi-Protocol Label Switching Link site to site network like both in same network
IDC Internet Data Center Buildings where we put servers
REST REpresentational State Transfer Architectural style defines a set of constraints on HTTP
CNAME Canonical Name A DNS record to point a/b/c domain to d domain so you don’t have to add A record in a/b/c

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  1. Copy existing jenkins folder, exclude workspace
  2. Modify jenkins port in Jenkins.xml, default 8080
  3. Modify AD Domain and rename an account to yours in config.xml

  4. Create / Start Jenkins service in cmd with administrator mode:

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    sc create <jenkins-service-name> <path/to/jenkins.exe>
    sc start <jenkins-service-name>

  5. View migrated jenkins in your browser with port specify above, default http://localhost:8080

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If you want to understand how Redux work, createStore(reducer) is the core function you should know and try to implement yourself. Here is a basic example of Redux, don’t worry I will break it down later :

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