Kwil Gateway(KGW) Go Client

This package provides a Go client for interacting with a Kwil Gateway(KGW).

The major feature this client provides compared to core/client is cookie-based authentication for data privacy concerned read requests. It'll automatically try to authenticate with the gateway if the gateway requires it.

This package is used by the kwil-cli to interact with the Kwil Gateway, mainly the kwil-cli database call subcommand. When you specify --authenticate flag, kwil-cli database call will use this gateway client to make the request.

Usage

Get familiar with core/client

Read the core/client README to get familiar with the basic functionalities of the client. The core/gatewayclient package is built on top of core/client, so you can use all the functionalities provided by core/client.

Create a Kwil Gateway Client

To use this client, you need to create a new client with the NewClient function from github.com/kwilteam/kwil-db/core/gatewayclient package.

clt, err := gatewayclient.NewClient(ctx, kgwProvider, &gatewayclient.GatewayOptions{
    Options: clientType.Options{
        Signer: &auth.EthPersonalSigner{Key: *pk},
    },
    AuthSignFunc: nil,
})

Options

GatewayOptions is a struct that embeds github.com/kwilteam/kwil-db/core/types/client.Options.

It also has two other optional fields:

• AuthSignFunc, allows you to provide a custom signing function for authentication, you can use it to do extra logic when the message is signed. If not provided, the client will use the default function which just call signer.Sign([]byte(message)).
• AuthCookieHandler, allows you to do extra logic when the cookie jar tries to save cookie.

An example using those options in kwil-cli:

• Options, see core/client for more details.
• AuthSignFunc, to prompt the user to sign the message
• AuthCookieHandler, to save the cookie to a file every time the client receives a cookie.

// cmd/kwil-cli/cmds/common/roundtripper.go L66

client, err := gatewayclient.NewClient(ctx, conf.Provider, &gatewayclient.GatewayOptions{
    Options: clientConfig,
    AuthSignFunc: func(message string, signer auth.Signer) (*auth.Signature, error) {
        assumeYes, err := GetAssumeYesFlag(cmd)
        if err != nil {
            return nil, err
        }

        if !assumeYes {
            err := promptMessage(message)
            if err != nil {
                return nil, err
            }
        }

        toSign := []byte(message)
        sig, err := signer.Sign(toSign)
        if err != nil {
            return nil, err
        }

        return sig, nil
    },
    AuthCookieHandler: func(c *http.Cookie) error {
        // persist the cookie
        return SaveCookie(KGWAuthTokenFilePath(), providerDomain, clientConfig.Signer.Identity(), c)
    },
})