com.slack.api.bolt.aws_lambda.response.ApiGatewayResponse Maven / Gradle / Ivy

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package com.slack.api.bolt.aws_lambda.response;

import com.google.gson.Gson;
import com.google.gson.GsonBuilder;
import lombok.extern.slf4j.Slf4j;

import java.nio.charset.StandardCharsets;
import java.util.Base64;
import java.util.Collections;
import java.util.HashMap;
import java.util.Map;

/**
 * The valid format of a response supposed to be sent.
 */
@Slf4j
public class ApiGatewayResponse {

    private static final Gson GSON = new GsonBuilder().create();

    private final int statusCode;
    private final String body;

    /**
     * Note: We cannot have multiple values with the same header name here.
     * See also "https://forums.aws.amazon.com/thread.jspa?threadID=205782"
     */
    private final Map headers;

    private final boolean isBase64Encoded;

    public ApiGatewayResponse(int statusCode, String body, Map headers, boolean isBase64Encoded) {
        this.statusCode = statusCode;
        this.body = body;
        this.headers = headers;
        this.isBase64Encoded = isBase64Encoded;
    }

    public int getStatusCode() {
        return statusCode;
    }

    public String getBody() {
        return body;
    }

    public Map getHeaders() {
        return headers;
    }

    // API Gateway expects the property to be called "isBase64Encoded" => isIs
    public boolean isIsBase64Encoded() {
        return isBase64Encoded;
    }

    public static Builder builder() {
        return new Builder();
    }

    public static class Builder {

        private int statusCode = 200;
        private Map headers = Collections.emptyMap();
        private String rawBody;
        private Object objectBody;
        private byte[] binaryBody;
        private boolean base64Encoded;

        public Builder statusCode(int statusCode) {
            this.statusCode = statusCode;
            return this;
        }

        public Builder headers(Map headers) {
            this.headers = headers;
            return this;
        }

        /**
         * Builds the {@link ApiGatewayResponse} using the passed raw body string.
         */
        public Builder rawBody(String rawBody) {
            this.rawBody = rawBody;
            return this;
        }

        /**
         * Builds the {@link ApiGatewayResponse} using the passed object body
         * converted to JSON.
         */
        public Builder objectBody(Object objectBody) {
            this.objectBody = objectBody;
            return this;
        }

        /**
         * Builds the {@link ApiGatewayResponse} using the passed binary body
         * encoded as base64. {@link #base64Encoded(boolean)
         * setBase64Encoded(true)} will be in invoked automatically.
         */
        public Builder binaryBody(byte[] binaryBody) {
            this.binaryBody = binaryBody;
            base64Encoded(true);
            return this;
        }

        /**
         * A binary or rather a base64encoded responses requires
         * 
         * "Binary Media Types" to be configured in API Gateway
         * 
a request with an "Accept" header set to one of the "Binary Media
         * Types"
         * 
         */
        public Builder base64Encoded(boolean base64Encoded) {
            this.base64Encoded = base64Encoded;
            return this;
        }

        public ApiGatewayResponse build() {
            String body = null;
            if (rawBody != null) {
                body = rawBody;
            } else if (objectBody != null) {
                body = GSON.toJson(objectBody);
            } else if (binaryBody != null) {
                body = new String(Base64.getEncoder().encode(binaryBody), StandardCharsets.UTF_8);
            }
            log.debug("body: {}", body);
            return new ApiGatewayResponse(statusCode, body, headers, base64Encoded);
        }
    }

    // ----------------------

    public static ApiGatewayResponse build302Response(String location) {
        Map headers = new HashMap<>();
        headers.put("Location", location);
        return ApiGatewayResponse.builder()
                .statusCode(302)
                .headers(headers)
                .build();
    }

}