# Fetch - Call API

## HTTP POST

使用 HTTP POST 傳送 JSON 資料到 Server

```csharp
Fetch f = new Fetch("https://httpbin.org/post");

// 自訂 header
f.Header = new
{
    Access_Token = "123456789"
};

// 自訂 cookie
f.Cookie = new
{
    account = "Gold"
};

// 查詢字串: ?qs=dog
var query_str = new
{
    qs = "dog"
};

// 傳送資料: { id: 100, ... }
var json_data = new
{
    id = 100,
    name = "zap",
    data = new List<object>()
    {
        new { sid=10, name="book" },
        new { sid=10, name="pen" },
    }
};

// 發出請求
string result = f.Post(json_data, query_str);

if (result == null) Console.WriteLine(f.GetResponse());
else Console.WriteLine(result);
```

**輸出：**

```javascript
{
  "args": {
    "qs": "dog"
  }, 
  "data": "{\"id\":100,\"name\":\"zap\",\"data\":[{\"sid\":10,\"name\":\"book\"},{\"sid\":10,\"name\":\"pen\"}]}", 
  "files": {}, 
  "form": {}, 
  "headers": {
    "Access-Token": "123456789", 
    "Content-Length": "81", 
    "Content-Type": "application/json; charset=utf-8", 
    "Cookie": "account=Gold", 
    "Host": "httpbin.org", 
    "X-Amzn-Trace-Id": "Root=1-5e7ed774-ad2d9263c688cd7cc7198855"
  }, 
  "json": {
    "data": [
      {
        "name": "book", 
        "sid": 10
      }, 
      {
        "name": "pen", 
        "sid": 10
      }
    ], 
    "id": 100, 
    "name": "zap"
  }, 
  "origin": "10.10.10.10", 
  "url": "https://httpbin.org/post?qs=dog"
}
```

## Other HTTP Methods

使用方式與 [HTTP POST](/zaplib2/fetch/fetch-get-json-response.md#http-post) 相似，只需將 Post 方法改為其他即可

```csharp
// 發出 Get 請求
string result = f.Get(json_data, query_str);

// 發出 Delete 請求
string result = f.Delete(json_data, query_str);

// 發出 Put 請求
string result = f.Put(json_data, query_str);

// 發出 Patch 請求
string result = f.Patch(json_data, query_str);
```

## Mapping JSON to Model

Fetch 使用 [Json.NET](https://www.newtonsoft.com/json) 提供的方法，將回應的 JSON 填充到指定物件中

### Declare Data Model

定義一個能夠承接回傳資料的類別，注意 JSON 的 **成員名稱** 與 **資料型態** 需要相同才可正常對應

```csharp
public class ModelResponse
{
    public string origin { get; set; }
    public string url { get; set; }
}
```

{% hint style="info" %}
如果 JSON 的成員名稱無法宣告成 Model，可以使用 [JsonProperty](https://www.newtonsoft.com/json/help/html/JsonPropertyName.htm) 指定命名
{% endhint %}

### Specify The Model

```csharp
Fetch f = new Fetch("https://httpbin.org/put");

ModelResponse result = f.Put<ModelResponse>();

if (result != null)
{
    Console.WriteLine("origin = " + result.origin);
    Console.WriteLine("url = " + result.url);
}
```

**輸出：**

```
origin = 10.10.10.10
url = https://httpbin.org/put
```

## Dynamic Request Configuration

Query String、Cookie 或 Header 不是固定的，都可使用 DynamicObject 類別動態組成

```csharp
// 動態新增成員的物件
DynamicObject dobj = new DynamicObject("MyQs");
dobj.CreateProperty("search_query", typeof(string), "柴犬");
object qs = dobj.CreateObject();

// 發處請求
Fetch f = new Fetch("https://www.youtube.com/results");
string result = f.Get(qs);
Console.WriteLine(result);
```

## Form Data

Fetch 預設 Content-Type 為 `application/json` 資料預設會編碼成 JSON 字串後傳送，但也支援 `application/x-www-form-urlencoded` 與 `multipart/form-data` MIME 編碼方式，只需指定即可

```csharp
Fetch f = new Fetch("https://httpbin.org/put");
// 指定內容 MIME 
f.ContentType = "application/x-www-form-urlencoded";
Console.WriteLine(f.Put(new { id = 100, name = "zap" }));
```

**輸出：**

Server 將接到 Form 編碼的資料

```csharp
{
  "args": {}, 
  "data": "", 
  "files": {}, 
  "form": {
    "id": "100", 
    "name": "zap"
  }, 
  "headers": {
    "Content-Length": "15", 
    "Content-Type": "application/x-www-form-urlencoded", 
    "Host": "httpbin.org", 
    "X-Amzn-Trace-Id": "Root=1-5e7ebcc6-df7bf161441274a690e0a4f0"
  }, 
  "json": null, 
  "origin": "10.10.10.10", 
  "url": "https://httpbin.org/put"
}
```

## Attach Files

傳送檔案預設以 `multipart/form-data` 的編碼方式傳送，只需指定檔案實體位置即可

```csharp
Fetch f = new Fetch("https://httpbin.org/post");
var data = new
{
    id = 999,
    name = "zap"
};
var files = new
{
    file1 = Environment.CurrentDirectory + "\\1.png",
    file2 = Environment.CurrentDirectory + "\\2.png"
};
Console.WriteLine(f.Post(data, null, files));
```

**輸出：**

檔案將以 Base64 方式編碼後至於 Form 中傳遞

```javascript
{
  "args": {}, 
  "data": "", 
  "files": {
    "file1": "data:application/octet-stream;base64,iVBORw0KGgoAAAANSUhEUgAA...", 
    "file2": "data:application/octet-stream;base64,iVBORw0KGgoAAAANSUhEUgAA..."
  }, 
  "form": {
    "id": "999", 
    "name": "zap"
  }, 
  "headers": {
    "Content-Length": "62936", 
    "Content-Type": "multipart/form-data; boundary=\"4dfd80e2-b5e2-444b-bd2b-fb50c75b7f14\"", 
    "Host": "httpbin.org", 
    "X-Amzn-Trace-Id": "Root=1-5e7ed5fe-5196074a652ff9ec70d878d1"
  }, 
  "json": null, 
  "origin": "10.10.10.10", 
  "url": "https://httpbin.org/post"
}
```

## Response Header

回應的訊息除了在 body 中，有部分資料也會帶在 header 中

```csharp
Fetch f = new Fetch("https://httpbin.org/get");
if (f.Get() != null)
{
    // 取得指定名稱 Header
    Console.WriteLine("Server : " + f.GetResponseHeader("Server"));
    
    // 取得指定名稱 Header 並自動轉型
    Console.WriteLine("Date : " + f.GetResponseHeader<DateTime>("Date"));
    
    // 取得全部 Header
    Console.WriteLine("\n全部:");
    foreach (var header in f.GetResponseHeaders())
        Console.WriteLine(header.Key + ": " + header.Value.First());
}
```

**輸出：**

```
Server : gunicorn/19.9.0
Date : 1999/3/9 下午 01:01:31

全部:
Connection: keep-alive
Access-Control-Allow-Origin: *
Access-Control-Allow-Credentials: true
Date: Sat, 09 Mar 1999 01:01:31 GMT
Server: gunicorn/19.9.0
```


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