Could not parse the JSON file ,Error in Progam.cs asp.net core

Question

I have some issues with the program.cs file, with the version of ASP.NetCORE 2.0

Here's my code

     public class Program
{
    public static void Main(string[] args)
    {
        BuildWebHost(args).Run();
    }

    public static IWebHost BuildWebHost(string[] args) =>
        WebHost.CreateDefaultBuilder(args)
            .UseContentRoot(Directory.GetCurrentDirectory())
            .UseIISIntegration()
            .UseKestrel()
            .UseStartup<Startup>()
            .UseConfiguration(new ConfigurationBuilder().AddCommandLine(args).Build())
            .Build();

}

When I run the project, following error occurs.

System.FormatException: 'Could not parse the JSON file. Error on line number '0': ''.'

How to resolve it?

I don't know , I just wanna run project .NET core and system throw exception like this Does you have any idea to fix ? — Runan Ngô, Sep 25 '17 at 06:54
Probably you add configuration files in the Startup class. Take a look there. — NtFreX, Sep 25 '17 at 07:03
I checked debug in startup file but it throw exception before pass startup file — Runan Ngô, Sep 25 '17 at 07:09
An empty file gives this problem, it has to consist of {} at the least. — Frode Nilsen, Jul 23 '18 at 08:10
The answer is that your `secrets.json` file must have been totally empty. There should at least be opening and closing braces as in `{}` or else it will throw error as it will not be a valid json file if empty. I wasted too much time too but finally figured it out, thanks to comment of @FrodeNilsen comment above — Jay Patel, Aug 22 '18 at 20:39
I had similar problem, and the problem was the ',' "GoogleReCaptcha". So silly. — Ali reza Soleimani Asl, Dec 30 '22 at 15:55

score 36 · Answer 1 · answered Jan 15 '18 at 14:27

36

Is your appSettings.json file (or whatever config you are using) formatted properly? WebHost.CreateDefaultBuilder will not be able to parse it correctly if there are invalid characters at the start. I saw this issue when a copy/paste added a space at the beginning of the file.

answered Jan 15 '18 at 14:27

ijb109

942
1
19
30

1

I have appsettings.Test.json file and it was empty. The error disappeared after I added empty {} to the JSON settings file. Thank you! – Ikigai programmeh Sep 09 '20 at 20:46
I made a console app and crashed into this error. In short: Thanks! Made an empty appsettings.json, I was only using local.settings.json. – Raymond A. Jun 08 '22 at 12:06
I had an extra comma (,) at the end of a line somewhere...that post saved me! – Holytoutant Sep 19 '22 at 17:16

score 29 · Answer 2 · answered Jul 11 '18 at 16:56

29

I had a a similar problem as this in another thread and posted my solution over there: Application Startup Failure with Json read Error. Posting it here as well in case it disappears.

I came across the same problem. In my case, I'd started implementing app secrets but left it halfway through. My secrets.json file was left linked but with invalid JSON.

Check your .csproj to see if a <UserSecretId> property is set under <PropertyGroup>. If it's set, BuildWebHost() will look through your secrets.json file in '%APPDATA%\Microsoft\UserSecrets\{secretId}', in addition to your appsettings.json file. An error in either file will cause the method to fail, but it won't tell you which file it is.

The solutions in my case were either to remove the <UserSecretId> property or

answered Jul 11 '18 at 16:56

Steepmountain

363
3
7

1

what a legend!!! I migrated to AWS Secret Manager and just cleared out my secrets file..... – The_Butcher Dec 17 '18 at 12:40
3

Ah, thanks. I've just cleared out my secrets.json. Leaving a pair of curly braces `{}` solved it. – ignotus Mar 04 '19 at 13:33
Amazing. The same exact thing happened to me. <3 u guys and stackoverflow – vullnetyy Oct 29 '20 at 19:57

score 14 · Answer 3 · answered Feb 14 '20 at 11:11

There is a possibility it might happen when appsettings.json is not properly formated

In my case, I had the below configuration and got the error

 {
"ConnectionStrings": {
"TransferDBConnection": 
 "Server=INGBTCPIC5DT04D;Database=TransferDB;Trusted_Connection=true;
 },
  ***{***
   "Logging": {
   "LogLevel": {
    "Default": "Warning"
   }
 },
 "AllowedHosts": "*"
}

ideally, it should be one extra { cause this problem

 {
 "ConnectionStrings": {
 "TransferDBConnection": 
 "Server=INGBTCPIC5DT04D;Database=TransferDB;Trusted_Connection=true;"
 },
  "Logging": {
  "LogLevel": {
    "Default": "Warning"
  }
},
"AllowedHosts": "*"
}

score 6 · Answer 4 · edited Nov 14 '19 at 02:09

6

Same problem and solved by removing <UserSecretsId> </UserSecretsId> from *.cproj.

It was a bad user secret configuration

edited Nov 14 '19 at 02:09

nuhkoca

1,777
4
20
44

answered Nov 14 '19 at 01:22

habib salimi

116
2
8

This was a great lead for my issue. Somehow the _secrets.json_ file was blank for the failing project. My solution was to add `{}` to my _secrets.json_ file. To edit the file, right-click on the project within the Solution Explorer and select Manage User Secrets. – jhenninger Apr 20 '20 at 21:37

score 6 · Answer 5 · answered Jan 13 '21 at 11:46

6

I had the same issue with one of my complex API's, sadly I've wasted few hours to find the issue.

First of all check whether your appsettings.json is well formatted as a standard JSON.

My issue was I've mistakenly typed some characters in the appsettings.json file like this, ( for me, 'ttings' characters cause this problem)

Also check whether all your json files are not empty. A standard json should at least have two curly braces.

answered Jan 13 '21 at 11:46

MrMalith

1,352
14
22

1

In my case i had empty appsettings.production.json file. Thank you. – Sam Alekseev Jul 10 '21 at 10:18

score 4 · Answer 6 · answered Feb 08 '18 at 19:45

4

I had this problem and the reason is that for some reason Visual Studio saves files with some invisible metadata that goes before the text therefore JSON reader cannot parse it.

You need to File -> Save As -> (Choose UTF-8 Without BOM).

answered Feb 08 '18 at 19:45

Stan

25,744
53
164
242

that was the solution in my case :) thanks – Basil Nov 12 '21 at 06:53

score 4 · Answer 7 · answered Jun 18 '20 at 09:50

4

In my case I had faced this issue as I had added User Secret to my solution and later removed all of its content including { }. Please make sure the content in the file is with proper JSON format. Or try providing an empty object { } to the file if no information needed from it.

answered Jun 18 '20 at 09:50

Biswamitra Kar

41
3

This is my case. – binaryDi Sep 11 '20 at 07:23

score 2 · Answer 8 · edited May 09 '19 at 18:17

2

I had the same problem.
I found that this problem seemed to have been caused by my appsettings.json file.
I copied a version from another place to solve this problem.

edited May 09 '19 at 18:17

geisterfurz007

5,292
5
33
54

answered May 08 '19 at 10:16

Jason

143
1
5

While this is not an answer, Please use comment section to ask additional or supplementary question. Thanks. – Shanteshwar Inde May 08 '19 at 10:43
1

@ShanteshwarInde I disagree. The answer explains that copying the file from somewhere else appears to solve the problem which is a valid answer. – geisterfurz007 May 09 '19 at 18:18
1

I also had a problem with my appsettings.json. Or more speciflcally, with my appsettings.production.json, which overlays the appsettings.json for the production build of my software. Earlier, my appsettings.production.json had curly braces with nothing in them as content. I had accidentally removed those curly braces, thinking an empty file would work too. It didn't. I didn't find out until I was deploying, because my appsettings.development.json *did* have correct content. Lesson learned: have empty braces in your overlaying appsettings files. – Jay May 20 '19 at 23:19
Thank you Jay! I messed things up when creating new environments and their appsettings.{environmentName}.json files were empty files. Added the curly braces to each file and it worked like a charm. Thank you again. – Blake Oct 16 '19 at 12:16

score 2 · Answer 9 · answered Jun 08 '20 at 07:15

in m case I put extra { right before (above) "ConnectionStrings" : in appsettings.json

I copied this from another file and assumed that "ConnectionStrings" : must inside a curly braces {}

before

...
},
{  //<-- this one the culprit
    "ConnectionStrings": {
      "Dapper": "Server=.;Database=Dapper;Trusted_Connection=True;"
    },

after

...
},
    "ConnectionStrings": {
      "Dapper": "Server=.;Database=Dapper;Trusted_Connection=True;"
    },

score 0 · Answer 10 · answered Apr 30 '18 at 12:49

0

Check if you don't have any hidden spaces or tabs in your json. You can use https://jsonlint.com/ to verify your json format.

answered Apr 30 '18 at 12:49

Enrico

2,734
1
27
40

score 0 · Answer 11 · answered Jul 13 '21 at 20:32

0

Check your appsettings.json file. that problem is because your file doesn't have a comma,brackets, Curly brackets or another punctuation sign.

answered Jul 13 '21 at 20:32

Carlos Rueda Valenzuela

1

score 0 · Answer 12 · answered Dec 15 '21 at 03:23

This issue could come if your appsetting.json is not well-formatted.

In my case somehow I'd an unwanted character in my appsettings.json

If you see carefully in sdk section I've got an extra l that only was causing the exception.

{
    "AppSettings": {
        "DefaultConnection": "ProdConnection",
        "DoGoogleAnalytics": "false"
    }, 
    "sdk": {l
        "version": "1.0.0"
    },
    "ConnectionStrings": {
        "LocalConnection": "data source=DATA_SERVER\\SQLEXPRESS,12345;initial catalog=DATABASE_NAME;persist security info=True;user id=db_user_id;password=db_password;MultipleActiveResultSets=true",
    }
}

score 0 · Answer 13 · answered Aug 09 '22 at 13:30

I had the same problem. The issues was a missing comma ',' after ConnectionString curly brackets in my appsettings.json. My appsettings.json was not properly formatted. So I only had to add the comma and that was it.

"ConnectionStrings": { "DefaultConnection": "Server=(local); Integrated Security= true; Database = PharmDataDB; MultipleActiveResultSet=true;" }

score -1 · Answer 14 · answered Feb 07 '22 at 08:31

-1

for me, it was missing comma in appsettings.json

answered Feb 07 '22 at 08:31

Mahmoud.Ismail

31
4

score -3 · Answer 15 · answered Nov 11 '20 at 11:58

-3

Just place ConnectionStrings in appsetting file then run the migration command.

answered Nov 11 '20 at 11:58

Murtaza

1
1

1

Please provide quality answers until you can write comments. This is not enough for an answer. – MoxxiManagarm Nov 11 '20 at 12:38

Could not parse the JSON file ,Error in Progam.cs asp.net core

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