Category Archives: Web Development

Breaking the Internet

ElasticSearch on AWS – Anonymous is not authorized to perform es:ESHttpGet

Hi everyone,

I am trying out ElasticSearch on AWS and ran into the following error while trying to access the provided Kabana endpoint:

{"Message":"User: anonymous is not authorized to perform: es:ESHttpGet"}

This turned out to be pretty simply, I just needed to whitelist my IP. Go to your search domain in the aws console, click access and finally select “Modify access policy”:

Then all you need to do is add another statement that gives your current ip access:

"Version": "2012-10-17", 
"Statement": [
 "Effect": "Allow",
"Principal": {
 "AWS": "*"
"Action": [
"Condition": {
"IpAddress": {
"aws:SourceIp": [
"Resource": "arn:aws:es:us-west-1:987654321098:domain/test-domain/*"

Feel free to comment below if you hit any issues, but I also found the following links pretty helpful:

Docker Volumes Mounting File as Folder on Windows

Hey everyone,

I ran into a small issue today using docker-compose. I had a config file I was trying to mount as a volume however running “docker-compose up” generated a folder instead.

ERROR: for grafana Cannot start service grafana: OCI runtime create failed: container_linux.go:349: starting container process caused “process_linux.go:449: container init caused \”rootfs_linux.go:58: mounting \\\”/host_mnt/e/repos/Sample-Twitch/grafana/datasources.yml\\\” to rootfs \\\”/var/lib/docker/overlay2/f5c9553407551b68dc5d5877d748ba2bf7d2f0dd2ad12c73e39be40af185c82d/merged\\\” at \\\”/var/lib/docker/overlay2/f5c9553407551b68dc5d5877d748ba2bf7d2f0dd2ad12c73e39be40af185c82d/merged/etc/grafana/provisioning/datasources/prometheus.yaml\\\” caused \\\”not a directory\\\”\””: unknown: Are you trying to mount a directory onto a file (or vice-versa)? Check if the specified host path exists and is the expected type ERROR: Encountered errors while bringing up the project.

The issue turned out to be an oversight on my part, I’d misspelled the config filename and docker was unable to find it. Consequently, it generated the missing file as a directory.

It took a bit of Googling to narrow this down, but eventually this stackoverflow post pointed me in the right direction:


Overwrite Selected Tree View Item Styles – Material UI ReactJS

Hi everyone,

Just a quick post on how to overwrite the styles of a selected tree item using material ui and ReactJS:

treeItem: {
paddingTop: theme.spacing(1),
‘&[aria-selected=”true”][aria-expanded=”true”] > div:nth-of-type(1)’: {
backgroundColor: ‘red’,

This will make the background color red for ONLY the selected item:


Failed to load the development https certificate using docker and ocelot

Hey everyone,

I randomly started encountering the following error while using docker to host my Ocelot gateway:

Failed to load the development https certificate at ‘/root/.aspnet/https/ContentGateway.pfx’.

The solution ended up being to clean out as many temp files as possible, especially the generated certs:

  • Delete the following files: Delete the C:\Users{USER}\AppData\Roaming\ASP.NET\Https folder
  • Clean the solution. Delete the bin and obj folders (I just did this for the gateway project)
  • Restart visual studio/visual code

I’ll add an update if I can narrow down what caused the initial issue but for now this seems to work.

Thanks to the following links for the info:

DX20807: Unable to retrieve document from: ‘[PII is hidden. For more details, see]

Hi everyone,

I ran into the following error today while implementing Azure AD B2C:

DX20807: Unable to retrieve document from: ‘[PII is hidden. For more details, see

There are a lot of different solutions to this error posted on Stackoverflow, Github, etc but without anything else to go on it’s pretty hard to narrow down the cause. This is where the ShowPII property comes in handy:

var resultJson = configuration.GetSection(“AzureAdB2cConfiguration”).Value;
var azureConfig = JsonConvert.DeserializeObject(resultJson);

Microsoft.IdentityModel.Logging.IdentityModelEventSource.ShowPII = true; // TODO: This should be removed in production and the authority url changed to https

jwtOptions.RequireHttpsMetadata = false; // TODO: This should be removed in production and the authority url changed to https
jwtOptions.Authority = azureConfig.Authority;
jwtOptions.Audience = azureConfig.AppClientId;
jwtOptions.Events = new JwtBearerEvents {
OnAuthenticationFailed = AuthenticationFailed,

static Task AuthenticationFailed(AuthenticationFailedContext arg)
// For debugging purposes only!
var s = $”AuthenticationFailed: {arg.Exception.Message}”;
arg.Response.ContentLength = s.Length;

return arg.Response.Body.WriteAsync(Encoding.UTF8.GetBytes(s), 0, s.Length);

Simply set Microsoft.IdentityModel.Logging.IdentityModelEventSource.ShowPII to true while configuration your authentication and the full internal error will be shown instead of the vague PII message.

In my case this turned out to be an issue with the construction of my authority url.


Element does not match nay field or property of Class – MongoDb and .net core

Hey everyone,

I ran into the following error today while searching MongoDb for an object:

Element ‘Tags’ does not match any field or property of class X.

The issue was that there were extra fields on the returned document that were not specified on the mapping target object. A bit of Googling revealed that there is a provided attribute that allows you to ignore all extra fields.

Simply add [BsonIgnoreExtraElements] to any relevant model definitions.

Thanks to this stackoverflow post for the lead:

.Net Core Web Api Returning Binary File with No Headers Instead of Expected Response

Hey everyone,

A small issue I’ve run into while setting up a .net core web api microservice that also utilises a number of gRPC services. Symptoms were as follows:

Response Read via Fiddler
– HTTP/1.0 200 This buggy server did not return headers
– Value was binary and unable to be read

Server logs

03:59:23 DBG] Connection id “0HM01U963EUAR” accepted.
[03:59:23 DBG] Connection id “0HM01U963EUAR” started.
[03:59:23 DBG] Connection id “0HM01U963EUAR”: HTTP/2 connection error.
Microsoft.AspNetCore.Server.Kestrel.Core.Internal.Http2.Http2ConnectionErrorException: HTTP/2 connection error (PROTOCOL_ERROR): Invalid HTTP/2 connection preface.
at Microsoft.AspNetCore.Server.Kestrel.Core.Internal.Http2.Http2Connection.ParsePreface(ReadOnlySequence`1& buffer, SequencePosition& consumed, SequencePosition& examined)
at Microsoft.AspNetCore.Server.Kestrel.Core.Internal.Http2.Http2Connection.TryReadPrefaceAsync()
at Microsoft.AspNetCore.Server.Kestrel.Core.Internal.Http2.Http2Connection.ProcessRequestsAsync[TContext](IHttpApplication`1 application)
[03:59:23 DBG] Connection id “0HM01U963EUAR” is closed. The last processed stream ID was 0.
[03:59:23 VRB] Connection id “0HM01U963EUAR” sending GOAWAY frame for stream ID 0 with length 8 and flags 0x0
[03:59:23 DBG] Connection id “0HM01U963EUAR” stopped.
[03:59:23 DBG] Connection id “0HM01U963EUAR” sending FIN because: “The Socket transport’s send loop completed gracefully.”

The issue turned out to be that in appSettings.json the default kestrel endpoint had been set to utilise http2. Removing this immediately resolved the issue. It may also be worth double checking your launch settings, startup.cs and program.cs to ensure that nothing’s been overridden.

I expect that any similar routing issues would result in similar symptoms so hopefully this post will be able to save a few people a bit time!


Unable to find the target operating system for the project

Hi everyone,

I ran into the following error today after updating visual studio 2019 to version 16.6:

unable to find the target operating system for the project

I tried a fair few things to get this going again and I’m assuming they’re not all necessary, but I’ll list them just in case:
– Clean solution
– Close visual studio
– Delete .vs folder
– Ensure that docker-compose is set as startup project
– Edit each project’s .csproj file and ensure that the DockerDefaultTargetOS value is set: Linux
– Edit docker-compose.dcproj and ensure that DocketTargetOS is set
– Restart computer

If you’re able to narrow it down at all I’d be interested in hearing what the actual cause is!


OpenXml Validation Spreadsheet Value Between Two Numbers – C#

Hi everyone,

Just a quick post on how to validate a numeric cell to ensure that the value is between two numbers when using OpenXml:

// Restrict min and max values
var dataValidations = new DocumentFormat.OpenXml.Spreadsheet.DataValidations { Count = 0 };
DocumentFormat.OpenXml.Spreadsheet.DataValidation dataValidation;
dataValidation = new DocumentFormat.OpenXml.Spreadsheet.DataValidation {
Type = DataValidationValues.Decimal,
AllowBlank = false,
SequenceOfReferences = new ListValue() { InnerText = $”{columnName}2:{columnName}1048576″ },
Operator = DataValidationOperatorValues.Between,
Formula1 = new Formula1 { Text = “10 “},
Formula2 = new Formula2 { Text = “20 “},

The snippet above will ensure that any values are between 10 and 20. I didn’t come across any examples for this while searching, so hopefully this will be able to help someone else out!