# GetContextKeysForCustomPolicy
<a name="API_GetContextKeysForCustomPolicy"></a>

Gets a list of all of the context keys referenced in the input policies. The policies are supplied as a list of one or more strings. To get the context keys from policies associated with an IAM user, group, or role, use [GetContextKeysForPrincipalPolicy](https://docs.aws.amazon.com/IAM/latest/APIReference/API_GetContextKeysForPrincipalPolicy.html).

Context keys are variables maintained by AWS and its services that provide details about the context of an API query request. Context keys can be evaluated by testing against a value specified in an IAM policy. Use `GetContextKeysForCustomPolicy` to understand what key names and values you must supply when you call [SimulateCustomPolicy](https://docs.aws.amazon.com/IAM/latest/APIReference/API_SimulateCustomPolicy.html). Note that all parameters are shown in unencoded form here for clarity but must be URL encoded to be included as a part of a real HTML request.

## Request Parameters
<a name="API_GetContextKeysForCustomPolicy_RequestParameters"></a>

 For information about the parameters that are common to all actions, see [Common Parameters](CommonParameters.md).

 **PolicyInputList.member.N**   
A list of policies for which you want the list of context keys referenced in those policies. Each document is specified as a string containing the complete, valid JSON text of an IAM policy.  
The [regex pattern](http://wikipedia.org/wiki/regex) used to validate this parameter is a string of characters consisting of the following:  
+ Any printable ASCII character ranging from the space character (`\u0020`) through the end of the ASCII character range
+ The printable characters in the Basic Latin and Latin-1 Supplement character set (through `\u00FF`)
+ The special characters tab (`\u0009`), line feed (`\u000A`), and carriage return (`\u000D`)
Type: Array of strings  
Length Constraints: Minimum length of 1. Maximum length of 131072.  
Pattern: `[\u0009\u000A\u000D\u0020-\u00FF]+`   
Required: Yes

## Response Elements
<a name="API_GetContextKeysForCustomPolicy_ResponseElements"></a>

The following element is returned by the service.

 **ContextKeyNames.member.N**   
The list of context keys that are referenced in the input policies.  
Type: Array of strings  
Length Constraints: Minimum length of 5. Maximum length of 256.

## Errors
<a name="API_GetContextKeysForCustomPolicy_Errors"></a>

For information about the errors that are common to all actions, see [Common Error Types](CommonErrors.md).

 ** InvalidInput **   
The request was rejected because an invalid or out-of-range value was supplied for an input parameter.  
HTTP Status Code: 400

## Examples
<a name="API_GetContextKeysForCustomPolicy_Examples"></a>

### Example 1
<a name="API_GetContextKeysForCustomPolicy_Example_1"></a>

In the following example, the request includes a policy as a string. The response shows that the policies use both `aws:CurrentTime` and `aws:username`.

#### Sample Request
<a name="API_GetContextKeysForCustomPolicy_Example_1_Request"></a>

```
https://iam.amazonaws.com/?Action=GetContextKeysForCustomPolicy
&PolicyInputList.member.1='{
  "Version": "2012-10-17",		 	 	 
  "Statement": {
    "Effect": "Allow",
    "Action": "dynamodb:*",
    "Resource": "arn:aws:dynamodb:us-east-2:ACCOUNT-ID-WITHOUT-HYPHENS:table/${aws:username}",
    "Condition":{"DateGreaterThan":{"aws:CurrentTime":"2015-08-16T12:00:00Z"}}
  }
}'
&Version=2010-05-08
&AUTHPARAMS
```

#### Sample Response
<a name="API_GetContextKeysForCustomPolicy_Example_1_Response"></a>

```
<GetContextKeysForCustomPolicyResponse xmlns="https://iam.amazonaws.com/doc/2010-05-08/">
  <GetContextKeysForCustomPolicyResult>
    <ContextKeyNames>
      <member>aws:username</member>
      <member>aws:CurrentTime</member>
    </ContextKeyNames>
  </GetContextKeysForCustomPolicyResult>
  <ResponseMetadata>
    <RequestId>d6808605-4c06-11e5-b121-bd8c7EXAMPLE</RequestId>
  </ResponseMetadata>
</GetContextKeysForCustomPolicyResponse>
```

## See Also
<a name="API_GetContextKeysForCustomPolicy_SeeAlso"></a>

For more information about using this API in one of the language-specific AWS SDKs, see the following:
+  [AWS Command Line Interface V2](https://docs.aws.amazon.com/goto/cli2/iam-2010-05-08/GetContextKeysForCustomPolicy) 
+  [AWS SDK for .NET V4](https://docs.aws.amazon.com/goto/DotNetSDKV4/iam-2010-05-08/GetContextKeysForCustomPolicy) 
+  [AWS SDK for C\$1\$1](https://docs.aws.amazon.com/goto/SdkForCpp/iam-2010-05-08/GetContextKeysForCustomPolicy) 
+  [AWS SDK for Go v2](https://docs.aws.amazon.com/goto/SdkForGoV2/iam-2010-05-08/GetContextKeysForCustomPolicy) 
+  [AWS SDK for Java V2](https://docs.aws.amazon.com/goto/SdkForJavaV2/iam-2010-05-08/GetContextKeysForCustomPolicy) 
+  [AWS SDK for JavaScript V3](https://docs.aws.amazon.com/goto/SdkForJavaScriptV3/iam-2010-05-08/GetContextKeysForCustomPolicy) 
+  [AWS SDK for Kotlin](https://docs.aws.amazon.com/goto/SdkForKotlin/iam-2010-05-08/GetContextKeysForCustomPolicy) 
+  [AWS SDK for PHP V3](https://docs.aws.amazon.com/goto/SdkForPHPV3/iam-2010-05-08/GetContextKeysForCustomPolicy) 
+  [AWS SDK for Python](https://docs.aws.amazon.com/goto/boto3/iam-2010-05-08/GetContextKeysForCustomPolicy) 
+  [AWS SDK for Ruby V3](https://docs.aws.amazon.com/goto/SdkForRubyV3/iam-2010-05-08/GetContextKeysForCustomPolicy)