# Access binary files in Lambda using an API Gateway API
The following OpenAPI example demonstrates how to access a binary file in Amazon Lambda through an API Gateway API. This API exposes the `GET /lambda?key={file-name}` and the `PUT /lambda?key={file-name}` methods for downloading and uploading a specified image file. The `GET` method returns the image file as a base64-encoded string as part of a JSON output, following the supplied mapping template, in a 200 OK response. The `PUT` method takes a raw binary blob as input and returns a 200 OK response with an empty payload.
You create the Lambda function that your API calls, and it must return a base64-encoded string with the `Content-Type` header of `application/json`.
**Topics**
+ [OpenAPI file of a sample API to access images in Lambda](#api-gateway-content-encodings-example-image-lambda-swagger-file)
+ [Download an image from Lambda](#api-gateway-content-encodings-example-download-image-from-lambda)
+ [Upload an image to Lambda](#api-gateway-content-encodings-example-upload-image-to-lambda)
## OpenAPI file of a sample API to access images in Lambda
The following OpenAPI file shows an example API that illustrates downloading an image file from Lambda and uploading an image file to Lambda.
------
#### [ OpenAPI 3.0 ]
```
{
"openapi": "3.0.0",
"info": {
"version": "2016-10-21T17:26:28Z",
"title": "ApiName"
},
"paths": {
"/lambda": {
"get": {
"parameters": [
{
"name": "key",
"in": "query",
"required": false,
"schema": {
"type": "string"
}
}
],
"responses": {
"200": {
"description": "200 response",
"content": {
"application/json": {
"schema": {
"$ref": "#/components/schemas/Empty"
}
}
}
},
"500": {
"description": "500 response"
}
},
"x-amazon-apigateway-integration": {
"uri": "arn:aws:apigateway:us-east-1:lambda:path/2015-03-31/functions/arn:aws:lambda:us-east-1:123456789012:function:image/invocations",
"type": "AWS",
"credentials": "arn:aws:iam::123456789012:role/Lambda",
"httpMethod": "POST",
"requestTemplates": {
"application/json": "{\n \"imageKey\": \"$input.params('key')\"\n}"
},
"responses": {
"default": {
"statusCode": "500"
},
"2\\d{2}": {
"statusCode": "200",
"responseTemplates": {
"application/json": "{\n \"image\": \"$input.body\"\n}"
}
}
}
}
},
"put": {
"parameters": [
{
"name": "key",
"in": "query",
"required": false,
"schema": {
"type": "string"
}
}
],
"responses": {
"200": {
"description": "200 response",
"content": {
"application/json": {
"schema": {
"$ref": "#/components/schemas/Empty"
}
},
"application/octet-stream": {
"schema": {
"$ref": "#/components/schemas/Empty"
}
}
}
},
"500": {
"description": "500 response"
}
},
"x-amazon-apigateway-integration": {
"uri": "arn:aws:apigateway:us-east-1:lambda:path/2015-03-31/functions/arn:aws:lambda:us-east-1:123456789012:function:image/invocations",
"type": "AWS",
"credentials": "arn:aws:iam::123456789012:role/Lambda",
"httpMethod": "POST",
"contentHandling": "CONVERT_TO_TEXT",
"requestTemplates": {
"application/json": "{\n \"imageKey\": \"$input.params('key')\", \"image\": \"$input.body\"\n}"
},
"responses": {
"default": {
"statusCode": "500"
},
"2\\d{2}": {
"statusCode": "200"
}
}
}
}
}
},
"x-amazon-apigateway-binary-media-types": [
"application/octet-stream",
"image/jpeg"
],
"servers": [
{
"url": "https://abcdefghi.execute-api.us-east-1.amazonaws.com/{basePath}",
"variables": {
"basePath": {
"default": "/v1"
}
}
}
],
"components": {
"schemas": {
"Empty": {
"type": "object",
"title": "Empty Schema"
}
}
}
}
```
------
#### [ OpenAPI 2.0 ]
```
{
"swagger": "2.0",
"info": {
"version": "2016-10-21T17:26:28Z",
"title": "ApiName"
},
"host": "abcdefghi.execute-api.us-east-1.amazonaws.com",
"basePath": "/v1",
"schemes": [
"https"
],
"paths": {
"/lambda": {
"get": {
"produces": [
"application/json"
],
"parameters": [
{
"name": "key",
"in": "query",
"required": false,
"type": "string"
}
],
"responses": {
"200": {
"description": "200 response",
"schema": {
"$ref": "#/definitions/Empty"
}
},
"500": {
"description": "500 response"
}
},
"x-amazon-apigateway-integration": {
"uri": "arn:aws:apigateway:us-east-1:lambda:path/2015-03-31/functions/arn:aws:lambda:us-east-1:123456789012:function:image/invocations",
"type": "AWS",
"credentials": "arn:aws:iam::123456789012:role/Lambda",
"httpMethod": "POST",
"requestTemplates": {
"application/json": "{\n \"imageKey\": \"$input.params('key')\"\n}"
},
"responses": {
"default": {
"statusCode": "500"
},
"2\\d{2}": {
"statusCode": "200",
"responseTemplates": {
"application/json": "{\n \"image\": \"$input.body\"\n}"
}
}
}
}
},
"put": {
"produces": [
"application/json", "application/octet-stream"
],
"parameters": [
{
"name": "key",
"in": "query",
"required": false,
"type": "string"
}
],
"responses": {
"200": {
"description": "200 response",
"schema": {
"$ref": "#/definitions/Empty"
}
},
"500": {
"description": "500 response"
}
},
"x-amazon-apigateway-integration": {
"uri": "arn:aws:apigateway:us-east-1:lambda:path/2015-03-31/functions/arn:aws:lambda:us-east-1:123456789012:function:image/invocations",
"type": "AWS",
"credentials": "arn:aws:iam::123456789012:role/Lambda",
"httpMethod": "POST",
"contentHandling" : "CONVERT_TO_TEXT",
"requestTemplates": {
"application/json": "{\n \"imageKey\": \"$input.params('key')\", \"image\": \"$input.body\"\n}"
},
"responses": {
"default": {
"statusCode": "500"
},
"2\\d{2}": {
"statusCode": "200"
}
}
}
}
}
},
"x-amazon-apigateway-binary-media-types" : ["application/octet-stream", "image/jpeg"],
"definitions": {
"Empty": {
"type": "object",
"title": "Empty Schema"
}
}
}
```
------
## Download an image from Lambda
To download an image file (`image.jpg`) as a binary blob from Lambda:
```
GET /v1/lambda?key=image.jpg HTTP/1.1
Host: abcdefghi.execute-api.us-east-1.amazonaws.com
Content-Type: application/json
Accept: application/octet-stream
```
The successful response looks like the following:
```
200 OK HTTP/1.1
[raw bytes]
```
To download an image file (`image.jpg`) as a base64-encoded string (formatted as a JSON property) from Lambda:
```
GET /v1/lambda?key=image.jpg HTTP/1.1
Host: abcdefghi.execute-api.us-east-1.amazonaws.com
Content-Type: application/json
Accept: application/json
```
The successful response looks like the following:
```
200 OK HTTP/1.1
{
"image": "W3JhdyBieXRlc10="
}
```
## Upload an image to Lambda
To upload an image file (`image.jpg`) as a binary blob to Lambda:
```
PUT /v1/lambda?key=image.jpg HTTP/1.1
Host: abcdefghi.execute-api.us-east-1.amazonaws.com
Content-Type: application/octet-stream
Accept: application/json
[raw bytes]
```
The successful response looks like the following:
```
200 OK
```
To upload an image file (`image.jpg`) as a base64-encoded string to Lambda:
```
PUT /v1/lambda?key=image.jpg HTTP/1.1
Host: abcdefghi.execute-api.us-east-1.amazonaws.com
Content-Type: application/json
Accept: application/json
W3JhdyBieXRlc10=
```
The successful response looks like the following:
```
200 OK
```