如何在 Go 语言中避免重复编码？

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我刚刚开始接触 go，我的背景包括泛型。由于 go 仍然 不支持泛型，我想知道如何保持代码干燥？

看看下面的示例，request 参数具有动态类型，它返回动态响应 (paymentmethodresponse)。如果我想创建另一个请求，我可以将整个代码复制并粘贴到方法中，仅更改 request 和 response 以及 localvarpath 变量的类型。

/*
paymentmethods returns available payment methods.
queries the available payment methods for a transaction based on the transaction context (like amount, country, and currency). besides giving back a list of the available payment methods, the response also returns which input details you need to collect from the shopper (to be submitted to `/payments`).  although we highly recommend using this endpoint to ensure you are always offering the most up-to-date list of payment methods, its usage is optional. you can, for example, also cache the `/paymentmethods` response and update it once a week.
 * @param request paymentmethodsrequest - reference of paymentmethodsrequest).
 * @param ctxs ..._context.context - optional, for authentication, logging, cancellation, deadlines, tracing, etc. passed from http.request or context.background().
@return paymentmethodsresponse
*/

func (a *checkout) paymentmethods(request *paymentmethodsrequest, ctxs ..._context.context) (paymentmethodsresponse, *_nethttp.response, error) {
    var (
        localvarhttpmethod  = _nethttp.methodpost
        localvarpostbody    interface{}
        localvarreturnvalue paymentmethodsresponse
    )

    // create path and map variables
    localvarpath := a.basepath() + "/paymentmethods"
    localvarheaderparams := make(map[string]string)
    localvarqueryparams := _neturl.values{}

    // to determine the content-type header
    localvarhttpcontenttypes := []string{"application/json"}

    // set content-type header
    localvarhttpcontenttype := common.selectheadercontenttype(localvarhttpcontenttypes)
    if localvarhttpcontenttype != "" {
        localvarheaderparams["content-type"] = localvarhttpcontenttype
    }

    // to determine the accept header
    localvarhttpheaderaccepts := []string{"application/json"}

    // set accept header
    localvarhttpheaderaccept := common.selectheaderaccept(localvarhttpheaderaccepts)
    if localvarhttpheaderaccept != "" {
        localvarheaderparams["accept"] = localvarhttpheaderaccept
    }
    // body params
    if request != nil {
        localvarpostbody = request
    }

    var ctx _context.context
    if len(ctxs) == 1 {
        ctx = ctxs[0]
    }

    r, err := a.client.preparerequest(ctx, localvarpath, localvarhttpmethod, localvarpostbody, localvarheaderparams, localvarqueryparams)
    if err != nil {
        return localvarreturnvalue, nil, err
    }

    localvarhttpresponse, err := a.client.callapi(r)
    if err != nil || localvarhttpresponse == nil {
        return localvarreturnvalue, localvarhttpresponse, err
    }

    localvarbody, err := _ioutil.readall(localvarhttpresponse.body)
    localvarhttpresponse.body.close()
    if err != nil {
        return localvarreturnvalue, localvarhttpresponse, err
    }

    if localvarhttpresponse.statuscode >= 300 {
        newerr := common.newapierror(localvarbody, localvarhttpresponse.status)
        return localvarreturnvalue, localvarhttpresponse, newerr
    }

    err = a.client.decode(&localvarreturnvalue, localvarbody, localvarhttpresponse.header.get("content-type"))
    if err != nil {
        newerr := common.newapierror(localvarbody, err.error())
        return localvarreturnvalue, localvarhttpresponse, newerr
    }

    return localvarreturnvalue, localvarhttpresponse, nil
}

使用示例：（请求是 json 结构）

res, httpRes, err := client.Checkout.PaymentMethods(&checkout.PaymentMethodsRequest{})

解决方案

您可以使用与 json.unmarshal 和其他接受 interface{} 类型参数的解码器/解组器所使用的方法相同的方法，而不是返回未知类型的值，而是将操作结果存储到其中提供的 interface{} 参数。

这里是示例伪代码：

func apicall(req, res interface{}) error {
    inputbody, err := jsonencode(req)
    if err != nil {
        return err
    }

    response, err := httpclient.postrequest(inputbody)
    if err != nil {
        return err
    }

    return jsondecode(res, response.body)
}

func main() {
    req := new(PaymentMethodsRequest)
    res := new(PaymentMethodsResponse)
    if err := apicall(req, res); err != nil {
        return err
    }

    // do something with res
}

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