filtering.go
1.68 KB
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package webutility
import (
"fmt"
"net/http"
"net/url"
"strings"
)
type Filter map[string]string
func (f *Filter) Size() int {
return len(*f)
}
func (f *Filter) Valid() bool {
return len(*f) > 0
}
func (fs Filter) validate(validFilters []string) (Filter, bool) {
goodFilters := make(map[string]string)
cnt := 0
len := 0
for f, _ := range fs {
len++
for _, v := range validFilters {
if f == v {
cnt++
goodFilters[f] = fs[f]
}
}
}
result := true
if len > 0 && cnt == 0 {
// if no valid filters are found declare filtering request as invalid
result = false
}
return goodFilters, result
}
// requires input in format: "param1::value1|param2::value2..."
func ParseFilters(req *http.Request, header string) (filters Filter) {
q := req.FormValue(header)
q = strings.Trim(q, "\"")
kvp := strings.Split(q, "|")
filters = make(map[string]string, len(kvp))
for i, _ := range kvp {
kv := strings.Split(kvp[i], "::")
if len(kv) == 2 {
key, _ := url.QueryUnescape(kv[0])
val, _ := url.QueryUnescape(kv[1])
filters[key] = val
}
}
return filters
}
// TODO(marko): very dodgy, needs more robustness
func MakeFilterString(prefix string, filters Filter, validFilters []string) (res string, ok bool) {
if prefix != "" {
prefix += "."
}
if len(filters) == 0 {
return "", true
}
filters, ok = filters.validate(validFilters)
if !ok {
return "", ok
}
symbol := "="
for k, v := range filters {
if res != "" {
res += " and "
} else {
res += " where "
}
c := string(v[0])
if c == "<" || c == ">" {
symbol = "" // examples: >3, >=3
} else {
symbol = "="
}
res += fmt.Sprintf("%s%s %s '%s'", prefix, k, symbol, v)
}
return res, ok
}