HttpClientHandler Class

The handler and options for communication to remote server

This class can be used to configure HTTP and HTTPS communication.

Also see Proxy for the product wide proxy configuration.

For HTTPS (SSL/TLS) communication, the server certificate's trustworthiness is verified using the system's default trust store (CA certificate store). If the server certificate's trustworthiness cannot be determined, the connection to the server is aborted.

The default trust store is:

• Windows:

  The Windows certificate store for "Trusted Root Certification Authorities" is used. You can manually install the root certificate of a private CA on a computer by using the CertMgr tool. The certificate store is only available if the user profile has been loaded.

• Linux:

  The certificates available in CAfile and CApath are trusted:

  • CAfile:

    The file can contain a concatenated sequence of CA certificates in PEM format.

    The SDK searches for the file at the following locations:

    • The file of your local OpenSSL installation (if libssl.so is found), or
    • the environment variable SSL_CERT_FILE, or
    • the default location /etc/ssl/cert.pem.

  • CApath:

    A directory containing CA certificates in PEM format. The files are looked up by the CA subject name hash value, e.g. 9d66eef0.0.

    The SDK searches for the directory at the following locations:

    • The directory of your local OpenSSL installation (if libssl.so is found), or
    • the environment variable SSL_CERT_DIR, or
    • the default location /etc/ssl/certs/.

• macOS:

  The trusted certificates from the macOS keychain are used. You can manually install the root certificate of a private CA by dragging the certificate file onto the Keychain Access app.

You can add more certificates to the trust store using AddTrustedCertificate(Stream).

Instances of this class can be used in multiple threads concurrently, as long as they are not modified concurrently.