way easier way to handle pagination

This commit is contained in:
Nils Stinnesbeck 2023-03-26 19:57:06 +02:00
parent c2f0f06b59
commit d47c0c8603
Signed by: nils
GPG Key ID: 9AEBF097A4042590
2 changed files with 37 additions and 170 deletions

139
client.go
View File

@ -3,13 +3,8 @@
package netboxapi package netboxapi
import ( import (
"bytes"
"encoding/json"
"fmt" "fmt"
"io"
"net/http"
e "git.stinnesbeck.com/nils/errorhandler"
transport "github.com/go-openapi/runtime/client" transport "github.com/go-openapi/runtime/client"
"github.com/netbox-community/go-netbox/v3/netbox/client" "github.com/netbox-community/go-netbox/v3/netbox/client"
) )
@ -21,13 +16,6 @@ type NetBoxAPI struct {
URL string URL string
} }
type apiResponse struct {
Count int64 `json:"count"`
Next string `json:"next"`
Previous string `json:"previous"`
Results []any `json:"results"`
}
// NewNetBoxClient returns a client to NetBox at the given url, // NewNetBoxClient returns a client to NetBox at the given url,
// using the provided token // using the provided token
func NewNetBoxClient(token string, url string) (NetBoxAPI, error) { func NewNetBoxClient(token string, url string) (NetBoxAPI, error) {
@ -50,130 +38,3 @@ func NewNetBoxClient(token string, url string) (NetBoxAPI, error) {
} }
return nb, nil return nb, nil
} }
func (nb NetBoxAPI) handleRawPagination(url string) (*apiResponse, error) {
var response apiResponse
b, err := nb.rawNetBoxAPICall(url, http.MethodGet)
if err != nil {
return nil, e.FormatError("can't perform raw NetBox API call", err)
}
// Unmarshal json into response
if err := json.Unmarshal(b, &response); err != nil {
return nil, e.FormatError("can't unmarshal json payload in raw NetBox API call", err)
}
// there are no more pages left, return the response we got
if response.Next == "" {
return &response, nil
}
// there are more pages left, get more responses from there
// recursive calling of handlePagination to get all following pages
nextResponse, err := nb.handleRawPagination(response.Next)
if err != nil {
return nil, e.FormatError("can't get next response from api", err)
}
// append all next responses' results to this response's result
response.Results = append(response.Results, nextResponse.Results...)
// go back up the chain through recursion
return &response, nil
}
func (nb NetBoxAPI) handlePagination(url string, payload any) error {
response, err := nb.handleRawPagination(url)
if err != nil {
return e.FormatError("can't handle pagination for url "+url, err)
}
fmt.Println(response.Count)
// cast response into our payload
if err := resultToOtherStructure(*response, &payload); err != nil {
return e.FormatError("can't parse result to other Structure", err)
}
// prettify.Print(payload)
return nil
}
func resultToOtherStructure(input apiResponse, output any) error {
// get JSON representation of results
c, err := json.Marshal(input.Results)
if err != nil {
return err
}
// Unmarshal onto specific structure via output
return json.Unmarshal(c, &output)
}
func (nb NetBoxAPI) rawNetBoxAPICall(url string, method string, data ...any) ([]byte, error) {
// construct complete URL (url already comes with a "/" after the "/api" part)
// url = fmt.Sprintf("https://%s/api%s", nb.URL, url)
// log.Printf("calling API on url: %s with method %s and data %+v\n", url, method, data)
// create new transport client
c := &http.Client{}
var req *http.Request
switch method {
case http.MethodPatch, http.MethodPost, http.MethodPut:
// to patch something we need data, check it exists
if data == nil {
return nil, fmt.Errorf("no data was provided, please provide data to use PATCH")
}
payload, err := json.Marshal(data)
if err != nil {
return nil, e.FormatError(fmt.Sprintf("can't marshal data %+v for apicall %s", data, url), err)
}
// construct request
innerRequest, err := http.NewRequest(method, url, bytes.NewBuffer(payload))
if err != nil {
return nil, e.FormatError(fmt.Sprintf("can't construct new request (method: %s, URL: %s, payload %s)", method, url, payload), err)
}
// hand over request to outer request
req = innerRequest
case http.MethodGet:
innerRequest, err := http.NewRequest(method, url, nil)
if err != nil {
return nil, e.FormatError(fmt.Sprintf("can't construct new request (method: %s, URL: %s)", method, url), err)
}
// hand over request to outer request
req = innerRequest
}
// set request headers
req.Header.Set("Content-Type", "application/json")
req.Header.Set("Authorization", fmt.Sprintf("Token %s", nb.Token))
// call API client with request
resp, err := c.Do(req)
if err != nil {
return nil, e.FormatError("can't get response from "+url, err)
}
defer resp.Body.Close()
// read body of response
body, err := io.ReadAll(resp.Body)
if err != nil {
return nil, e.FormatError("can't read response body", err)
}
switch resp.StatusCode {
case 200, 201:
return body, nil
default:
return body, fmt.Errorf("got bad StatusCode %d in response from API, data is:\n\t-> %+v", resp.StatusCode, data)
}
}

44
ipam.go
View File

@ -34,14 +34,12 @@ func (nb NetBoxAPI) GetPrefixes(param ipam.IpamPrefixesListParams) ([]*models.Pr
return nil, e.FormatError("can't get prefixes", err) return nil, e.FormatError("can't get prefixes", err)
} }
// variable to hold all prefixes to return
var prefixesToReturn []*models.Prefix
// append first page of models
prefixesToReturn = append(prefixesToReturn, prefixes.Payload.Results...)
// check if there are more prefixes on other pages // check if there are more prefixes on other pages
if prefixes.Payload.Next != nil { if prefixes.Payload.Next == nil {
// return the results of the first batch, there are no others
return prefixes.Payload.Results, nil
}
// there are more pages to get // there are more pages to get
// calculate new offset // calculate new offset
@ -55,11 +53,12 @@ func (nb NetBoxAPI) GetPrefixes(param ipam.IpamPrefixesListParams) ([]*models.Pr
if err != nil { if err != nil {
return nil, e.FormatError("can't get prefixes", err) return nil, e.FormatError("can't get prefixes", err)
} }
// append the results from next page to our prefixes to return
prefixesToReturn = append(prefixesToReturn, nextPagePrefixes...)
}
return prefixesToReturn, nil // append the results from next page to our prefixes to return
prefixes.Payload.Results = append(prefixes.Payload.Results, nextPagePrefixes...)
// return all prefixes
return prefixes.Payload.Results, nil
} }
// GetIPAddresses returns IP addresses from the api filtered by the parameter list param // GetIPAddresses returns IP addresses from the api filtered by the parameter list param
@ -90,20 +89,27 @@ func (nb NetBoxAPI) GetIPAddresses(param ipam.IpamIPAddressesListParams) ([]*mod
// check if there are no more prefixes on other pages // check if there are no more prefixes on other pages
if addresses.Payload.Next == nil { if addresses.Payload.Next == nil {
// return the results of the first batch, there are no others! // return the results of the first batch, there are no others
return addresses.Payload.Results, nil return addresses.Payload.Results, nil
} }
// variable to hold all prefixes to return // there are more pages to get
var addressesToReturn []*models.IPAddress
if err := nb.handlePagination(addresses.Payload.Next.String(), &addressesToReturn); err != nil { // calculate new offset
return nil, e.FormatError("can't handle Pagination", err) newOffset := *param.Offset + *param.Limit
// set new offset
param.Offset = &newOffset
// get prefixes from next page
nextPageIPAddresses, err := nb.GetIPAddresses(param)
if err != nil {
return nil, e.FormatError("can't get IP addresses", err)
} }
// append append first batch to the other batches // append the results from next page to our prefixes to return
addressesToReturn = append(addressesToReturn, addresses.Payload.Results...) addresses.Payload.Results = append(addresses.Payload.Results, nextPageIPAddresses...)
// return all addresses // return all addresses
return addressesToReturn, nil return addresses.Payload.Results, nil
} }