Add API to download device-type agent

components/application-mgt/org.wso2.carbon.device.application.mgt.api/src/main/java/org/wso2/carbon/device/application/mgt/api/services/ArtifactDownloadAPI.java

@@ -131,4 +131,41 @@ public interface ArtifactDownloadAPI {
                     value = "UUID of the application release.",
                     required = true)
             @PathParam("uuid") String uuid);
+
+    @GET
+    @Path("/{deviceType}/agent/{tenantId}")
+    @Produces(MediaType.APPLICATION_OCTET_STREAM)
+    @ApiOperation(
+            produces = MediaType.APPLICATION_OCTET_STREAM,
+            httpMethod = "GET",
+            value = "get the agent of a device type",
+            notes = "This will download an agent depending on the device type"
+    )
+    @ApiResponses(
+            value = {
+                    @ApiResponse(
+                            code = 200,
+                            message = "OK. \n Successfully got the agent.",
+                            response = ApplicationList.class),
+                    @ApiResponse(
+                            code = 404,
+                            message = "Not Found. There doesn't have an defined agent for the resource." +
+                                      "query."),
+                    @ApiResponse(
+                            code = 500,
+                            message = "Internal Server Error. \n Error occurred while getting the agent.",
+                            response = ErrorResponse.class)
+            })
+    Response getAndroidAgent(
+            @ApiParam(
+                    name = "deviceType",
+                    value = "Device type of the agent.",
+                    example = "android",
+                    required = true)
+            @PathParam("deviceType") String deviceType,
+            @ApiParam(
+                    name = "tenantId",
+                    value = "Tenant Id of the application artifact belongs.",
+                    required = true)
+            @PathParam("tenantId") int tenantId);
 }

components/application-mgt/org.wso2.carbon.device.application.mgt.api/src/main/java/org/wso2/carbon/device/application/mgt/api/services/impl/ArtifactDownloadAPIImpl.java

@@ -110,4 +110,44 @@ public class ArtifactDownloadAPIImpl implements ArtifactDownloadAPI {
             return Response.status(Response.Status.INTERNAL_SERVER_ERROR).entity(msg).build();
         }
     }
+
+    @GET
+    @Override
+    @Produces(MediaType.APPLICATION_OCTET_STREAM)
+    @Path("/{deviceType}/agent/{tenantId}")
+    public Response getAndroidAgent(@PathParam("deviceType") String deviceType,
+                                    @PathParam("tenantId") int tenantId) {
+        AppmDataHandler dataHandler = APIUtil.getDataHandler();
+        try (InputStream fileInputStream = dataHandler.getAgentStream(tenantId, deviceType)) {
+            byte[] content = IOUtils.toByteArray(fileInputStream);
+            try (ByteArrayInputStream binaryDuplicate = new ByteArrayInputStream(content)) {
+                Response.ResponseBuilder response = Response
+                        .ok(binaryDuplicate, MediaType.APPLICATION_OCTET_STREAM);
+                response.status(Response.Status.OK);
+                response.header("Content-Disposition", "attachment; filename=\"" + deviceType + " agent\"");
+                response.header("Content-Length", content.length);
+                return response.build();
+            } catch (IOException e) {
+                String msg = "Error occurred while creating input stream from buffer array. ";
+                log.error(msg, e);
+                return Response.status(Response.Status.INTERNAL_SERVER_ERROR).entity(msg).build();
+            }
+        } catch (NotFoundException e) {
+            String msg = "Couldn't find an agent for device type: " + deviceType;
+            log.error(msg, e);
+            return Response.status(Response.Status.NOT_FOUND).entity(msg).build();
+        } catch (BadRequestException e){
+            String msg = "Invalid device type received: " + deviceType + ".Valid device type is android";
+            log.error(msg, e);
+            return Response.status(Response.Status.BAD_REQUEST).entity(msg).build();
+        } catch (ApplicationManagementException e) {
+            String msg = "Error occurred while getting the application release artifact file. ";
+            log.error(msg, e);
+            return Response.status(Response.Status.INTERNAL_SERVER_ERROR).entity(msg).build();
+        } catch (IOException e) {
+            String msg = "Error occurred while getting the byte array of application release artifact file. ";
+            log.error(msg, e);
+            return Response.status(Response.Status.INTERNAL_SERVER_ERROR).entity(msg).build();
+        }
+    }
 }

components/application-mgt/org.wso2.carbon.device.application.mgt.common/src/main/java/org/wso2/carbon/device/application/mgt/common/services/ApplicationStorageManager.java

@@ -20,6 +20,7 @@ package org.wso2.carbon.device.application.mgt.common.services;
 import org.wso2.carbon.device.application.mgt.common.ApplicationInstaller;
 import org.wso2.carbon.device.application.mgt.common.dto.ApplicationReleaseDTO;
 import org.wso2.carbon.device.application.mgt.common.exception.ApplicationStorageManagementException;
+import org.wso2.carbon.device.application.mgt.common.exception.RequestValidatingException;
 import org.wso2.carbon.device.application.mgt.common.exception.ResourceManagementException;
 
 import java.io.InputStream;
@@ -110,4 +111,15 @@ public interface ApplicationStorageManager {
      */
     InputStream getFileStream(String hashVal, String folderName, String fileName, int tenantId)
             throws ApplicationStorageManagementException;
+
+    /**
+     * Get the InputStream of the file which is located in filePath
+     *
+     * @param deviceType device type name
+     * @param tenantId   local tenant's id
+     * @return {@link InputStream}
+     * @throws ApplicationStorageManagementException throws if an error occurs when accessing the file.
+     */
+    InputStream getFileStream(String deviceType, int tenantId)
+            throws ApplicationStorageManagementException, RequestValidatingException;
 }

components/application-mgt/org.wso2.carbon.device.application.mgt.common/src/main/java/org/wso2/carbon/device/application/mgt/common/services/AppmDataHandler.java

@@ -37,4 +37,15 @@ public interface AppmDataHandler {
 
     InputStream getArtifactStream(int tenantId, String uuid, String folderName, String artifactName)
             throws ApplicationManagementException;
+
+    /**
+     * Get agent apk
+     *
+     * @param tenantId   local tenant
+     * @param deviceType device type name
+     * @return {@link InputStream}
+     * @throws ApplicationManagementException throws if an error occurs when accessing the file.
+     */
+    InputStream getAgentStream(int tenantId, String deviceType)
+            throws ApplicationManagementException;
 }

components/application-mgt/org.wso2.carbon.device.application.mgt.core/src/main/java/org/wso2/carbon/device/application/mgt/core/impl/ApplicationStorageManagerImpl.java

@@ -20,12 +20,14 @@ package org.wso2.carbon.device.application.mgt.core.impl;
 import com.dd.plist.NSDictionary;
 import net.dongliu.apk.parser.bean.ApkMeta;
 import org.apache.commons.io.IOUtils;
+import org.apache.commons.lang.StringUtils;
 import org.apache.commons.logging.Log;
 import org.apache.commons.logging.LogFactory;
 import org.wso2.carbon.device.application.mgt.common.ApplicationInstaller;
 import org.wso2.carbon.device.application.mgt.common.dto.ApplicationReleaseDTO;
 import org.wso2.carbon.device.application.mgt.common.DeviceTypes;
 import org.wso2.carbon.device.application.mgt.common.exception.ApplicationStorageManagementException;
+import org.wso2.carbon.device.application.mgt.common.exception.RequestValidatingException;
 import org.wso2.carbon.device.application.mgt.common.exception.ResourceManagementException;
 import org.wso2.carbon.device.application.mgt.common.services.ApplicationStorageManager;
 import org.wso2.carbon.device.application.mgt.core.exception.ParsingException;
@@ -249,6 +251,28 @@ public class ApplicationStorageManagerImpl implements ApplicationStorageManager
         }
     }
 
+    @Override
+    public InputStream getFileStream(String deviceType, int tenantId)
+            throws ApplicationStorageManagementException, RequestValidatingException {
+        if (StringUtils.isNotBlank(deviceType) && deviceType.equals("android")) {
+            String fileName = Constants.ANDROID_AGENT;
+            String filePath =
+                    storagePath + File.separator + "agents" + File.separator + deviceType + File.separator
+                    + tenantId + File.separator + fileName;
+            try {
+                return StorageManagementUtil.getInputStream(filePath);
+            } catch (IOException e) {
+                String msg = "Error occured when accessing the file in file path: " + filePath;
+                log.error(msg, e);
+                throw new ApplicationStorageManagementException(msg, e);
+            }
+        } else {
+            String msg = "Error occurred while accessing the file invalid device type: " + deviceType;
+            log.error(msg);
+            throw new RequestValidatingException(msg);
+        }
+    }
+
     /***
      * This method is responsible to  delete artifact file which is located in the artifact path.
      *

components/application-mgt/org.wso2.carbon.device.application.mgt.core/src/main/java/org/wso2/carbon/device/application/mgt/core/impl/AppmDataHandlerImpl.java

@@ -24,11 +24,13 @@ import org.wso2.carbon.device.application.mgt.common.config.LifecycleState;
 import org.wso2.carbon.device.application.mgt.common.exception.ApplicationManagementException;
 import org.wso2.carbon.device.application.mgt.common.exception.ApplicationStorageManagementException;
 import org.wso2.carbon.device.application.mgt.common.exception.LifecycleManagementException;
+import org.wso2.carbon.device.application.mgt.common.exception.RequestValidatingException;
 import org.wso2.carbon.device.application.mgt.common.services.ApplicationStorageManager;
 import org.wso2.carbon.device.application.mgt.common.services.AppmDataHandler;
 import org.wso2.carbon.device.application.mgt.common.config.UIConfiguration;
 import org.wso2.carbon.device.application.mgt.core.dao.ApplicationReleaseDAO;
 import org.wso2.carbon.device.application.mgt.core.dao.common.ApplicationManagementDAOFactory;
+import org.wso2.carbon.device.application.mgt.core.exception.BadRequestException;
 import org.wso2.carbon.device.application.mgt.core.util.DAOUtil;
 import org.wso2.carbon.device.application.mgt.core.exception.ApplicationManagementDAOException;
 import org.wso2.carbon.device.application.mgt.core.exception.NotFoundException;
@@ -76,7 +78,7 @@ public class AppmDataHandlerImpl implements AppmDataHandler {
             InputStream inputStream = applicationStorageManager
                     .getFileStream(appReleaseHashValue, folderName, artifactName, tenantId);
             if (inputStream == null) {
-                String msg = "Couldn't file the file in the file system.";
+                String msg = "Couldn't find the file in the file system.";
                 log.error(msg);
                 throw new ApplicationManagementException(msg);
             }
@@ -94,4 +96,28 @@ public class AppmDataHandlerImpl implements AppmDataHandler {
             ConnectionManagerUtil.closeDBConnection();
         }
     }
+
+    @Override
+    public InputStream getAgentStream(int tenantId, String deviceType)
+            throws ApplicationManagementException {
+        ApplicationStorageManager applicationStorageManager = DAOUtil.getApplicationStorageManager();
+        try {
+            InputStream inputStream = applicationStorageManager
+                    .getFileStream(deviceType, tenantId);
+            if (inputStream == null) {
+                String msg = "Couldn't find the file in the file system for device type: " + deviceType;
+                log.error(msg);
+                throw new NotFoundException(msg);
+            }
+            return inputStream;
+        } catch (ApplicationStorageManagementException e) {
+            String msg = "Error occurred when getting input stream of the " + deviceType + " agent.";
+            log.error(msg, e);
+            throw new ApplicationManagementException(msg, e);
+        } catch (RequestValidatingException e) {
+            String msg = "Error invalid request received with device type: " + deviceType;
+            log.error(msg, e);
+            throw new BadRequestException(msg, e);
+        }
+    }
 }

components/application-mgt/org.wso2.carbon.device.application.mgt.core/src/main/java/org/wso2/carbon/device/application/mgt/core/util/Constants.java

@@ -61,6 +61,8 @@ public class Constants {
     public  static final String SUBSCRIBED = "SUBSCRIBED";
     public  static final String UNSUBSCRIBED = "UNSUBSCRIBED";
 
+    public static final String ANDROID_AGENT = "android-agent.apk";
+
 
     /**
      * Database types supported by Application Management.