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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
ACL Access Control List An ACL specifies which users or system processes are granted access to objects

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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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  1. Use React.PureComponent, it implement shouldComponentUpdate() by shallow compare prop and state, it is powerful with Immutable.js.
  2. Use Chrome extension and checked highlight updates in dev tool to find any unnecessary updates.
  3. Use React-virtualized for render huge list in small chunk at a time.

  4. Use Production build, for example with webpack you need following config:

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    new webpack.DefinePlugin({
        'process.env.NODE_ENV': JSON.stringify('production')
    }),
    new webpack.optimize.UglifyJsPlugin()