.NET API Docker部署仅暴露80端口且提示‘The 'file' scheme is not supported’

使用下述Dockerfile部署.NET API时，服务仅暴露80端口，且出现提示信息The 'file' scheme is not supported；但通过Visual Studio运行该Dockerfile时，服务可正常暴露443端口并运行。

Dockerfile内容：

FROM mcr.microsoft.com/dotnet/aspnet:6.0 AS base
WORKDIR /app
EXPOSE 80
EXPOSE 443

FROM mcr.microsoft.com/dotnet/sdk:6.0 AS build
WORKDIR /src
COPY ["RECashMachineBackend/RECashMachineBackend.csproj", "RECashMachineBackend/"]
COPY ["RECashMachineBackend.Repository/RECashMachineBackend.Repository.csproj", "RECashMachineBackend.Repository/"]
COPY ["RECashMachineBackend.Models/RECashMachineBackend.Models.csproj", "RECashMachineBackend.Models/"]
COPY ["RECashMachineBackend/nuget.config", ""]
# COPY ["*.props", "./"]

# ARG PAT=localhost
# RUN sed -i "s|</configuration>|<packageSourceCredentials><Techdome.Identity><add key=\"Username\" value=\"PAT\" /><add key=\"ClearTextPassword\" value=\"${PAT}\" /></Techdome.Identity></packageSourceCredentials></configuration>|" nuget.config

RUN dotnet restore "RECashMachineBackend/RECashMachineBackend.csproj" --configfile "./nuget.config"
COPY . .
WORKDIR "/src/RECashMachineBackend"
RUN dotnet build "RECashMachineBackend.csproj" -c Release -o /app/build

FROM build AS publish
RUN dotnet publish "RECashMachineBackend.csproj" -c Release -o /app/publish /p:UseAppHost=false

FROM base AS final
WORKDIR /app
COPY --from=publish /app/publish .
ENTRYPOINT ["dotnet", "RECashMachineBackend.dll"]

一、修复HTTPS端口暴露问题 #

Visual Studio运行Docker时会自动注入HTTPS相关环境变量和证书映射，手动部署时需显式配置：

• 在final阶段添加HTTPS环境变量，指定证书路径和端口：

  FROM base AS final
  WORKDIR /app
  COPY --from=publish /app/publish .
  # 添加HTTPS配置环境变量
  ENV ASPNETCORE_URLS="https://+;http://+"
  ENV ASPNETCORE_HTTPS_PORT=443
  ENV ASPNETCORE_Kestrel__Certificates__Default__Path=/https/aspnetapp.pfx
  ENV ASPNETCORE_Kestrel__Certificates__Default__Password="your-cert-password"
  # 挂载本地证书目录
  VOLUME ["/https"]
  ENTRYPOINT ["dotnet", "RECashMachineBackend.dll"]
  

• 启动容器时挂载本地证书目录并传递密码参数：

  docker run -d -p 80:80 -p 443:443 -v /your-local-cert-folder:/https -e ASPNETCORE_Kestrel__Certificates__Default__Password="your-cert-password" your-image-tag
  

二、解决The 'file' scheme is not supported错误 #

这个错误大多是因为应用尝试访问本地文件系统路径，但容器内路径无效，或者配置里用了file://协议的资源但容器内无法访问：

• 检查appsettings.json等配置文件，确认是否有指向本地文件的配置项，替换成容器内可访问的路径，或者改用其他存储方式
• 如果是证书路径问题，确保容器内证书路径和环境变量配置一致，且文件确实存在
• 发布时确认必要的静态文件、配置文件已经正确复制到/app/publish目录

内容的提问来源于stack exchange，提问作者Punit kumar