Swift

DynamoDB - Query

See more Amazon DynamoDB Examples

The Query operation finds items based on primary key values. You can query any table or secondary index that has a composite primary key (a partition key and a sort key). Swift

func chilkatTest() {
    var success: Bool = false

    let rest = CkoRest()!

    // Implements the following CURL command:

    // curl -X POST https://dynamodb.us-west-2.amazonaws.com/ \
    //   -H "Accept-Encoding: identity" \
    //   -H "Content-Type: application/x-amz-json-1.0" \
    //   -H "Authorization: AWS4-HMAC-SHA256 Credential=<Credential>, SignedHeaders=<Headers>, Signature=<Signature>" \
    //   -H "X-Amz-Date: <Date>" \
    //   -H "X-Amz-Target: DynamoDB_20120810.Query" \
    //   -d '{
    //     "TableName": "Reply",
    //     "IndexName": "PostedBy-Index",
    //     "Limit": 3,
    //     "ConsistentRead": true,
    //     "ProjectionExpression": "Id, PostedBy, ReplyDateTime",
    //     "KeyConditionExpression": "Id = :v1 AND PostedBy BETWEEN :v2a AND :v2b",
    //     "ExpressionAttributeValues": {
    //         ":v1": {"S": "Amazon DynamoDB#DynamoDB Thread 1"},
    //         ":v2a": {"S": "User A"},
    //         ":v2b": {"S": "User C"}
    //     },
    //     "ReturnConsumedCapacity": "TOTAL"
    // }'

    // Use the following online tool to generate REST code from a CURL command
    // Convert a cURL Command to REST Source Code

    let authAws = CkoAuthAws()!
    authAws.accessKey = "AWS_ACCESS_KEY"
    authAws.secretKey = "AWS_SECRET_KEY"
    // Don't forget to change the region to your particular region. (Also make the same change in the call to Connect below.)
    authAws.region = "us-west-2"
    authAws.serviceName = "dynamodb"
    // SetAuthAws causes Chilkat to automatically add the following headers: Authorization, X-Amz-Date
    rest.setAuthAws(authProvider: authAws)

    // URL: https://dynamodb.us-west-2.amazonaws.com/
    var bTls: Bool = true
    var port: Int = 443
    var bAutoReconnect: Bool = true
    success = rest.connect(hostname: "dynamodb.us-west-2.amazonaws.com", port: port, tls: bTls, autoReconnect: bAutoReconnect)
    if success != true {
        print("ConnectFailReason: \(rest.connectFailReason.intValue)")
        print("\(rest.lastErrorText!)")
        return
    }

    // Note: The above code does not need to be repeatedly called for each REST request.
    // The rest object can be setup once, and then many requests can be sent.  Chilkat will automatically
    // reconnect within a FullRequest* method as needed.  It is only the very first connection that is explicitly
    // made via the Connect method.

    // Use this online tool to generate code from sample JSON:
    // Generate Code to Create JSON

    // The following JSON is sent in the request body.

    // {
    //   "TableName": "Reply",
    //   "IndexName": "PostedBy-Index",
    //   "Limit": 3,
    //   "ConsistentRead": true,
    //   "ProjectionExpression": "Id, PostedBy, ReplyDateTime",
    //   "KeyConditionExpression": "Id = :v1 AND PostedBy BETWEEN :v2a AND :v2b",
    //   "ExpressionAttributeValues": {
    //     ":v1": {
    //       "S": "Amazon DynamoDB#DynamoDB Thread 1"
    //     },
    //     ":v2a": {
    //       "S": "User A"
    //     },
    //     ":v2b": {
    //       "S": "User C"
    //     }
    //   },
    //   "ReturnConsumedCapacity": "TOTAL"
    // }

    let json = CkoJsonObject()!
    json.updateString(jsonPath: "TableName", value: "Reply")
    json.updateString(jsonPath: "IndexName", value: "PostedBy-Index")
    json.updateInt(jsonPath: "Limit", value: 3)
    json.updateBool(jsonPath: "ConsistentRead", value: true)
    json.updateString(jsonPath: "ProjectionExpression", value: "Id, PostedBy, ReplyDateTime")
    json.updateString(jsonPath: "KeyConditionExpression", value: "Id = :v1 AND PostedBy BETWEEN :v2a AND :v2b")
    json.updateString(jsonPath: "ExpressionAttributeValues.:v1.S", value: "Amazon DynamoDB#DynamoDB Thread 1")
    json.updateString(jsonPath: "ExpressionAttributeValues.:v2a.S", value: "User A")
    json.updateString(jsonPath: "ExpressionAttributeValues.:v2b.S", value: "User C")
    json.updateString(jsonPath: "ReturnConsumedCapacity", value: "TOTAL")

    rest.addHeader(name: "Content-Type", value: "application/x-amz-json-1.0")
    rest.addHeader(name: "X-Amz-Target", value: "DynamoDB_20120810.Query")
    rest.addHeader(name: "Accept-Encoding", value: "identity")

    let sbRequestBody = CkoStringBuilder()!
    json.emitSb(sb: sbRequestBody)
    let sbResponseBody = CkoStringBuilder()!
    success = rest.fullRequestSb(httpVerb: "POST", uriPath: "/", requestBody: sbRequestBody, responseBody: sbResponseBody)
    if success != true {
        print("\(rest.lastErrorText!)")
        return
    }

    var respStatusCode: Int = rest.responseStatusCode.intValue
    print("response status code = \(respStatusCode)")
    if respStatusCode >= 400 {
        print("Response Status Code = \(respStatusCode)")
        print("Response Header:")
        print("\(rest.responseHeader!)")
        print("Response Body:")
        print("\(sbResponseBody.getAsString()!)")
        return
    }

    let jsonResponse = CkoJsonObject()!
    jsonResponse.loadSb(sb: sbResponseBody)

    jsonResponse.emitCompact = false
    print("\(jsonResponse.emit()!)")

    // Sample JSON response:
    // (Sample code for parsing the JSON response is shown below)

    // {
    //   "ConsumedCapacity": {
    //     "CapacityUnits": 1,
    //     "TableName": "Reply"
    //   },
    //   "Count": 2,
    //   "Items": [
    //     {
    //       "ReplyDateTime": {
    //         "S": "2015-02-18T20:27:36.165Z"
    //       },
    //       "PostedBy": {
    //         "S": "User A"
    //       },
    //       "Id": {
    //         "S": "Amazon DynamoDB#DynamoDB Thread 1"
    //       }
    //     },
    //     {
    //       "ReplyDateTime": {
    //         "S": "2015-02-25T20:27:36.165Z"
    //       },
    //       "PostedBy": {
    //         "S": "User B"
    //       },
    //       "Id": {
    //         "S": "Amazon DynamoDB#DynamoDB Thread 1"
    //       }
    //     }
    //   ],
    //   "ScannedCount": 2
    // }

    // Sample code for parsing the JSON response...
    // Use the following online tool to generate parsing code from sample JSON:
    // Generate Parsing Code from JSON

    var ReplyDateTimeS: String?
    var PostedByS: String?
    var IdS: String?

    var ConsumedCapacityCapacityUnits: Int = jsonResponse.int(of: "ConsumedCapacity.CapacityUnits").intValue
    var ConsumedCapacityTableName: String? = jsonResponse.string(of: "ConsumedCapacity.TableName")
    var Count: Int = jsonResponse.int(of: "Count").intValue
    var ScannedCount: Int = jsonResponse.int(of: "ScannedCount").intValue
    var i: Int = 0
    var count_i: Int = jsonResponse.size(ofArray: "Items").intValue
    while i < count_i {
        jsonResponse.i = i
        ReplyDateTimeS = jsonResponse.string(of: "Items[i].ReplyDateTime.S")
        PostedByS = jsonResponse.string(of: "Items[i].PostedBy.S")
        IdS = jsonResponse.string(of: "Items[i].Id.S")
        i = i + 1
    }


}