解析 Revel 中的 JSON 日期时间

huangapple
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英文:

Parsing a json datetime in revel

问题

我正在尝试从JSON请求中解析一个Datetime。请求的格式如下所示：

  1. {
  2.   "startedAt": "2017-06-01 10:39",
  3.   ...
  4. }

被解码为以下结构体：

  1. type MyStruct struct {
  2.   StartedAt time.Time `json:"startedAt" bson:"startedAt"`
  3.   ...
  4. }

解码行如下所示：

  1. json.NewDecoder(c.Request.Body).Decode(&MyStruct)

Revel返回以下错误：

  1. interface conversion: error is *time.ParseError, not *errors.Error

根据revel的文档（https://revel.github.io/manual/parameters.html），SQL标准的日期时间格式2006-01-02、2006-01-02 15:04是内置的。

在同一文档中，他们还说可以追加格式，如下所示：

  1. func init() {
  2.     revel.TimeFormats = append(revel.TimeFormats, "01/02/2006")
  3. }

为了验证格式是否在数组中，我尝试了以下代码：

  1. func init() {
  2.     revel.TimeFormats = append(revel.TimeFormats, "2016-06-01 12:12")
  3. }

在绝望之下，我尝试以revel返回JSON时间的相同格式提交：

  1. {
  2.   "startedAt": "2017-06-22T12:22:16.265618819-05:00",
  3.   ...
  4. }

目前我不确定该怎么办。有人能够成功解析Datetime吗？

更新：我尝试了RickyA的解决方案，但现在出现了解析错误。

  1. parsing time ""Mon, 02 Jan 2006 15:04:05 -0700"" as "Mon, 02 Jan 2006 15:04:05 -0700": cannot parse ""Mon, 02 Jan 2006 15:04:05 -0700"" as "Mon"

更奇怪的是，我实现了一个小技巧来解决这个问题。我将请求时间字段更改为字符串，并给它一个ToX函数来进行转换。该函数有效，但当它移动到UnmarshalJSON函数中时却失败了。

此外，我无法确定这是否是一个错误：

  1. func (t *AnyTime) UnmarshalJSON(b []byte) error {
  2.   fmt.Println(time.RFC1123Z)
  3.   fmt.Println(string(b))
  4.   fmt.Println(reflect.TypeOf(time.RFC1123Z))
  5.   fmt.Println(reflect.TypeOf(string(b)))
  6.   ...

这将输出：

  1. Mon, 02 Jan 2006 15:04:05 -0700
  2. "Mon, 02 Jan 2006 15:04:05 -0700"
  3. string
  4. string

请注意，只有一个字符串带有双引号。这让我相信，传递给UnmarshalJSON的字节数组中包含双引号。

最终更新：我相当确定双引号是有意的，从某种意义上讲，这是有道理的。UnmarshalJSON将从':'到','之间的所有内容传递，包括双引号。我猜这样做是为了支持整数和布尔值。我不喜欢这个解决方案，但这是我修复它的方法：

  1. func (t *AnyTime) UnmarshalJSON(b []byte) error {
  2.   var err error
  3.   sTime := string(b)
  4.   sTime = strings.TrimSuffix(sTime, "\"")
  5.   sTime = strings.TrimPrefix(sTime, "\"")
  6.   t.Time, err = time.Parse(time.RFC1123Z, sTime)
  7.   ...
英文:

I'm attempting to parse a Datetime in revel from a json request. The request looks something like this:

  1. {
  2.   "startedAt": "2017-06-01 10:39",
  3.   ...
  4. }

The struct it's being decoded into looks like this:

  1. type MyStruct struct {
  2.   StartedAt time.Time `json:"startedAt" bson:"startedAt"`
  3.   ...
  4. }

The decode line looks like this:

  1. json.NewDecoder(c.Request.Body).Decode(&MyStruct)

Revel returns this error:

  1. interface conversion: error is *time.ParseError, not *errors.Error

According to revel's documentation here, https://revel.github.io/manual/parameters.html

  1. The SQL standard date time formats of 2006-01-02, 2006-01-02 15:04 are built in.

In the same document, they also say you can append formats like this:

  1. func init() {
  2.     revel.TimeFormats = append(revel.TimeFormats, "01/02/2006")
  3. }

To verify the format was in the array, I tried this:

  1. func init() {
  2.     revel.TimeFormats = append(revel.TimeFormats, "2016-06-01 12:12")
  3. }

In a final act of desperation I tried submitting it in the same format that revel will return json times in:

  1. {
  2.   "startedAt": "2017-06-22T12:22:16.265618819-05:00",
  3.   ...
  4. }

At this point I'm not sure where to go with this. Has anyone been able to get revel to parse a Datetime?

Update: I tried RickyA's solution below, but now there is a parsing error.

  1. parsing time ""Mon, 02 Jan 2006 15:04:05 -0700"" as "Mon, 02 Jan 2006 15:04:05 -0700": cannot parse ""Mon, 02 Jan 2006 15:04:05 -0700"" as "Mon"

What's even stranger is that I implemented a bit of a hack to get this working in the interrum. I changed the request time field to a string, and gave it a ToX function which converted it. That function works, but when it's moved into the UnmarshalJSON function it fails.

Also, I can't tell if this is a bug or not:

  1. func (t *AnyTime) UnmarshalJSON(b []byte) error {
  2.   fmt.Println(time.RFC1123Z)
  3.   fmt.Println(string(b))
  4.   fmt.Println(reflect.TypeOf(time.RFC1123Z))
  5.   fmt.Println(reflect.TypeOf(string(b)))
  6.   ...

This outputs this:

  1. Mon, 02 Jan 2006 15:04:05 -0700
  2. "Mon, 02 Jan 2006 15:04:05 -0700"
  3. string
  4. string

Notice that only 1 of the string has double quotes. This is leading me to believe that some how the byte array passed to UnmarshalJSON has double quotes within its string.

Final Update: So I'm pretty sure the double quotes are intentional, and in a way it makes sense. The UnmarshalJSON is passing everything from the ':' through the ',' which includes the double quotes. I'm guessing this is done so that it can also support integers and booleans. I don't like the solution, but this is how I fixed it:

  1. func (t *AnyTime) UnmarshalJSON(b []byte) error {
  2.   var err error
  3.   sTime := string(b)
  4.   sTime = strings.TrimSuffix(sTime, "\"")
  5.   sTime = strings.TrimPrefix(sTime, "\"")
  6.   t.Time, err = time.Parse(time.RFC1123Z, sTime)
  7.   ...

答案1

得分: 3

我遇到了同样的问题，最后创建了一个自定义类型来处理time.Time。

  1. package genericfields
  3. import (
  4. 	"encoding/json"
  5. 	"time"
  6. 	"strings"
  8. 	"gopkg.in/mgo.v2/bson"
  9. )
  11. // ANYTIME //
  13. // AnyTime接受任何时间格式进行反序列化//
  14. type AnyTime struct{ time.Time }
  16. func (t AnyTime) MarshalJSON() ([]byte, error) {
  17. 	return json.Marshal(t.Time)
  18. }
  20. func (t *AnyTime) UnmarshalJSON(b []byte) error {
  21. 	err := json.Unmarshal(b, &t.Time)
  22. 	if err != nil { //假设输入的时间没有时区信息
  23. 		bstr := strings.Trim(string(b), `"`)
  24. 		t.Time, err = time.Parse("2006-01-02T15:04:05", bstr)
  25. 		if err != nil {
  26. 			return err //TODO 添加更多尝试的时间格式
  27. 		}
  28. 	}
  29. 	return nil
  30. }
  32. func (t AnyTime) GetBSON() (interface{}, error) {
  33. 	return t.Time, nil
  34. }
  36. func (t *AnyTime) SetBSON(raw bson.Raw) error {
  37. 	var tm time.Time
  38. 	err := raw.Unmarshal(&tm)
  39. 	if err != nil {
  40. 		return err
  41. 	}
  42. 	t.Time = tm.UTC()
  43. 	return nil
  44. }
  46. func (t AnyTime) ToTime() time.Time {
  47. 	return t.Time
  48. }

用法：

  1. type MyStruct struct {
  2.   StartedAt genericfields.AnyTime `json:"startedAt" bson:"startedAt"`
  3.   ...
  4. }

你可能需要调整time.Parse的输入格式。

英文:

I had the same problem and ended up creating a custom type for time.Time

  1. package genericfields
  3. import (
  4. 	"encoding/json"
  5. 	"time"
  6.     "strings"
  8. 	"gopkg.in/mgo.v2/bson"
  9. )
  11. // ANYTIME //
  13. // AnyTime accepts any time format for its unmarshaling //
  14. type AnyTime struct{ time.Time }
  16. func (t AnyTime) MarshalJSON() ([]byte, error) {
  17. 	return json.Marshal(t.Time)
  18. }
  20. func (t *AnyTime) UnmarshalJSON(b []byte) error {
  21. 	err := json.Unmarshal(b, &t.Time)
  22. 	if err != nil { //assume non tz time input
  23. 		bstr := strings.Trim(string(b), `"`)
  24. 	    t.Time, err = time.Parse("2006-01-02T15:04:05", bstr)
  25. 		if err != nil {
  26. 			return err //TODO add more formats to try
  27. 		}
  28. 	}
  29. 	return nil
  30. }
  32. func (t AnyTime) GetBSON() (interface{}, error) {
  33. 	return t.Time, nil
  34. }
  36. func (t *AnyTime) SetBSON(raw bson.Raw) error {
  37. 	var tm time.Time
  38. 	err := raw.Unmarshal(&tm)
  39. 	if err != nil {
  40. 		return err
  41. 	}
  42. 	t.Time = tm.UTC()
  43. 	return nil
  44. }
  46. func (t AnyTime) ToTime() time.Time {
  47. 	return t.Time
  48. }

Usage:

  1. type MyStruct struct {
  2.   StartedAt genericfields.AnyTime `json:"startedAt" bson:"startedAt"`
  3.   ...
  4. }

You might need to tweak the input for time.Parse somewhat.

huangapple
  • 本文由 发表于 2017年6月23日 01:24:42
  • 转载请务必保留本文链接：https://go.coder-hub.com/44705817.html
  • go
  • json
  • revel
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