Tcl

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). Tcl

load ./chilkat.dll

set success 0

set rest [new_CkRest]

# 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

set authAws [new_CkAuthAws]

CkAuthAws_put_AccessKey $authAws "AWS_ACCESS_KEY"
CkAuthAws_put_SecretKey $authAws "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.)
CkAuthAws_put_Region $authAws "us-west-2"
CkAuthAws_put_ServiceName $authAws "dynamodb"
# SetAuthAws causes Chilkat to automatically add the following headers: Authorization, X-Amz-Date
CkRest_SetAuthAws $rest $authAws

# URL: https://dynamodb.us-west-2.amazonaws.com/
set bTls 1
set port 443
set bAutoReconnect 1
set success [CkRest_Connect $rest "dynamodb.us-west-2.amazonaws.com" $port $bTls $bAutoReconnect]
if {$success != 1} then {
    puts "ConnectFailReason: [CkRest_get_ConnectFailReason $rest]"
    puts [CkRest_lastErrorText $rest]
    delete_CkRest $rest
    delete_CkAuthAws $authAws
    exit
}

# 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"
# }

set json [new_CkJsonObject]

CkJsonObject_UpdateString $json "TableName" "Reply"
CkJsonObject_UpdateString $json "IndexName" "PostedBy-Index"
CkJsonObject_UpdateInt $json "Limit" 3
CkJsonObject_UpdateBool $json "ConsistentRead" 1
CkJsonObject_UpdateString $json "ProjectionExpression" "Id, PostedBy, ReplyDateTime"
CkJsonObject_UpdateString $json "KeyConditionExpression" "Id = :v1 AND PostedBy BETWEEN :v2a AND :v2b"
CkJsonObject_UpdateString $json "ExpressionAttributeValues.:v1.S" "Amazon DynamoDB#DynamoDB Thread 1"
CkJsonObject_UpdateString $json "ExpressionAttributeValues.:v2a.S" "User A"
CkJsonObject_UpdateString $json "ExpressionAttributeValues.:v2b.S" "User C"
CkJsonObject_UpdateString $json "ReturnConsumedCapacity" "TOTAL"

CkRest_AddHeader $rest "Content-Type" "application/x-amz-json-1.0"
CkRest_AddHeader $rest "X-Amz-Target" "DynamoDB_20120810.Query"
CkRest_AddHeader $rest "Accept-Encoding" "identity"

set sbRequestBody [new_CkStringBuilder]

CkJsonObject_EmitSb $json $sbRequestBody
set sbResponseBody [new_CkStringBuilder]

set success [CkRest_FullRequestSb $rest "POST" "/" $sbRequestBody $sbResponseBody]
if {$success != 1} then {
    puts [CkRest_lastErrorText $rest]
    delete_CkRest $rest
    delete_CkAuthAws $authAws
    delete_CkJsonObject $json
    delete_CkStringBuilder $sbRequestBody
    delete_CkStringBuilder $sbResponseBody
    exit
}

set respStatusCode [CkRest_get_ResponseStatusCode $rest]
puts "response status code = $respStatusCode"
if {$respStatusCode >= 400} then {
    puts "Response Status Code = $respStatusCode"
    puts "Response Header:"
    puts [CkRest_responseHeader $rest]
    puts "Response Body:"
    puts [CkStringBuilder_getAsString $sbResponseBody]
    delete_CkRest $rest
    delete_CkAuthAws $authAws
    delete_CkJsonObject $json
    delete_CkStringBuilder $sbRequestBody
    delete_CkStringBuilder $sbResponseBody
    exit
}

set jsonResponse [new_CkJsonObject]

CkJsonObject_LoadSb $jsonResponse $sbResponseBody

CkJsonObject_put_EmitCompact $jsonResponse 0
puts [CkJsonObject_emit $jsonResponse]

# 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

set ConsumedCapacityCapacityUnits [CkJsonObject_IntOf $jsonResponse "ConsumedCapacity.CapacityUnits"]
set ConsumedCapacityTableName [CkJsonObject_stringOf $jsonResponse "ConsumedCapacity.TableName"]
set Count [CkJsonObject_IntOf $jsonResponse "Count"]
set ScannedCount [CkJsonObject_IntOf $jsonResponse "ScannedCount"]
set i 0
set count_i [CkJsonObject_SizeOfArray $jsonResponse "Items"]
while {$i < $count_i} {
    CkJsonObject_put_I $jsonResponse $i
    set ReplyDateTimeS [CkJsonObject_stringOf $jsonResponse "Items[i].ReplyDateTime.S"]
    set PostedByS [CkJsonObject_stringOf $jsonResponse "Items[i].PostedBy.S"]
    set IdS [CkJsonObject_stringOf $jsonResponse "Items[i].Id.S"]
    set i [expr $i + 1]
}

delete_CkRest $rest
delete_CkAuthAws $authAws
delete_CkJsonObject $json
delete_CkStringBuilder $sbRequestBody
delete_CkStringBuilder $sbResponseBody
delete_CkJsonObject $jsonResponse