HTTP Payload - C Sharp

The logic payload type when a task is invoked by an API Route trigger.

Class Reference

Type

• HttpPayload (type of Payload.Http)

Properties

Property	Type	Description
ApiGatewayIdentityContext	IdentityContext	API gateway permanent ID and name
ApiRouteIdentityContext	IdentityContext	API route permanent ID and name
RequestId	string	Request ID
Request	HttpRequest	Request content
Source	Peer?	Request source
Destination	Peer?	Request destination

IdentityContext

Property	Type	Description
PermanentIdentity	Guid	Identity permanent ID
Name	string	Identity name

Peer

Property	Type	Description
Address	Address	Peer address

Address

Property	Type
Protocol	string
Address	byte[]
Port	uint

HttpRequest

Data and metadata of the HTTP request.

Property	Type	Description	Example
Host	string	Request host name
Path	string	API route	/api/path
Scheme	string	HTTP scheme	http, https
Method	string	HTTP method	GET, POST, etc.
Version	string	HTTP version	HTTP/1.1
Headers	Dictionary<byte[], byte[]>	Request headers
Query	string	Querystring	param1=value1 (no question mark; empty string if no querystring available)
Data	byte[]	Request body (empty array if not available)

Examples

Parse Querystring

Assuming the querystring is

`?name=Arthur+Dent&age=42`

The parameters can be parsed as below:

Import namespace(s)

using System.Web;
using System.Collections.Specialized;

var payload = await ctx.GetPayload();

string? queryString = payload.Http?.Request.Query;
NameValueCollection? queryParams = null;

if (!String.IsNullOrWhiteSpace(queryString)) {
    queryParams = HttpUtility.ParseQueryString(queryString);
}

string? name = queryParams?["name"]; // null if not exist
int age = Convert.ToInt32(queryParams?["age"]); // 0 if not exist

Parse HTTP Payload body to JSON

Assuming the HTTP request includes a body with the following JSON string:

{
    "name": "Arthur Dent",
    "age": 42,
    "job": {
        "title": "Sandwich-maker",
        "salary": 0
    },
    "quotes": [
        "Is there any tea on this spaceship?",
        "This must be Thursday. I never could get the hang of Thursdays.",
        "Would it save you a lot of time if I just gave up and went mad now?"
    ]
}

We can parse the payload into a JsonNode object, if the content of the payload may not be fixed (with its elements automatically parsed as JsonValue, JsonObject or JsonArray):

Import namespace(s)

using System.Text;
using System.Text.Json.Nodes;

var payload = await ctx.GetPayload();

byte[]? data = payload.Http?.Request.Data;
JsonNode? parsed = null;

if (data is not null && data.Length > 0)
{
    string jsonString = Encoding.UTF8.GetString(data);
    parsed = JsonNode.Parse(jsonString);  // will fail if jsonString is not valid JSON
}

// get values (null if not exist)
string? name = parsed?["name"]?.GetValue<string>();
int? age = parsed?["age"]?.GetValue<int>();

// ...

See the example of Payload for checking the payload type.

See the example of session storage agent for how to use classes extended from JsonNode.

Advanced Examples

Parse HTTP Payload Into User-Defined Classes

Assuming the HTTP request includes a body as the previous example but always be fixed, we can define classes to match the data structure, which require a source generation context class for it to be deserialised properly:

Import namespace(s) and declare classes

using System.Text;
using System.Text.Json;
using System.Text.Json.Serialization;

internal class Person
{
    [JsonPropertyName("name")]
    public string? Name { get; set; }

    [JsonPropertyName("age")]
    public int? Age { get; set; }

    [JsonPropertyName("job")]
    public Job? Job { get; set; }

    [JsonPropertyName("quotes")]
    public List<string>? Quotes { get; set; }

    public Person(string name, int age, Job job, List<string> quotes)
    {
        Name = name;
        Age = age;
        Job = job;
        Quotes = quotes;
    }
}

internal class Job
{
    [JsonPropertyName("title")]
    public string? Title { get; set; }

    [JsonPropertyName("salary")]
    public int? Salary { get; set; }

    public Job(string title, int salary)
    {
        Title = title;
        Salary = salary;
    }
}

// source generation context for Person
[JsonSourceGenerationOptions()]
[JsonSerializable(typeof(Person))]
internal partial class PersonSourceGenerationContext : JsonSerializerContext
{
}

info

You can move user-defined classes into shared modules as public classes. See the tutorial for examples.

Then you can parse the HTTP payload into a Person object using JsonSerializer.Deserialize():

var payload = await ctx.GetPayload();

byte[]? data = payload.Http?.Request.Data;
Person? person = null;

if (data is not null && data.Length > 0)
{
    string jsonString = Encoding.UTF8.GetString(data);
    person = JsonSerializer.Deserialize<Person>(
        jsonString,
        PersonSourceGenerationContext.Default.Person
    );
}

if (person is not null)
{
    // read values from properties
    string name = person.name;
    int age = person.age;
    string title = person.job.title;
    List<string> quotes = person.quotes;
}