// dbasik provides a service with which to convert spreadsheets containing
// data to JSON for further processing.
// Copyright (C) 2024 M R Lemon
// This program is free software: you can redistribute it and/or modify
// it under the terms of the GNU General Public License as published by
// the Free Software Foundation, either version 3 of the License, or
// (at your option) any later version.
// This program is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
// GNU General Public License for more details.
// You should have received a copy of the GNU General Public License
// along with this program. If not, see <https://www.gnu.org/licenses/>.
package main
import (
"encoding/json"
"net/http"
"regexp"
)
// validateSpreadsheetCell checks that the cellRef is in a valid format
func validateSpreadsheetCell(cellRef string) bool {
pattern := `^[A-Z]+[1-9][0-9]*$`
regExp := regexp.MustCompile(pattern)
return regExp.MatchString(cellRef)
}
// We want this so that our JSON is nested under a key at the top, e.g. "Datamap:"...
type envelope map[string]interface{}
// writeJSON)Pretty() helper for sending responses - pretty prints output. This takes the destination http.ResponseWriter, the
// HTTP status code to sned, the data to encode to JSON and a header map containing any additional
// HTTP headers we want to include in the response.
func (app *application) writeJSONPretty(w http.ResponseWriter, status int, data envelope, headers http.Header) error {
// Encode the data to JSON, returing the error if there was one.
js, err := json.MarshalIndent(data, "", "\t")
if err != nil {
return err
}
// Append a newline to make it easier tro view in terminal applications
js = append(js, '\n')
// We know now that we won't encounter any more errors before writing the response,
// so it's safe to add any headers that we want to include. We loop through the
// header map and add each header to the http.ResponseWriter header map.
// Note that it's okay if the provided header map is nil. Go doesn't throw an error
// if you wanmt to try to range over (or more generally reader from) a nil map.
for key, value := range headers {
w.Header()[key] = value
}
// Add the "Content-Type: application/json" header, then write the status code and
// JSON response.
w.Header().Set("Content-Type", "application/json")
w.WriteHeader(status)
w.Write(js)
return nil
}
// writeJSON() helper for sending responses. This takes the destination http.ResponseWriter, the
// HTTP status code to sned, the data to encode to JSON and a header map containing any additional
// HTTP headers we want to include in the response.
func (app *application) writeJSON(w http.ResponseWriter, status int, data any, headers http.Header) error {
// Encode the data to JSON, returing the error if there was one.
js, err := json.Marshal(data)
if err != nil {
return err
}
// Append a newline to make it easier tro view in terminal applications
js = append(js, '\n')
// We know now that we won't encounter any more errors before writing the response,
// so it's safe to add any headers that we want to include. We loop through the
// header map and add each header to the http.ResponseWriter header map.
// Note that it's okay if the provided header map is nil. Go doesn't throw an error
// if you wanmt to try to range over (or more generally reader from) a nil map.
for key, value := range headers {
w.Header()[key] = value
}
// Add the "Content-Type: application/json" header, then write the status code and
// JSON response.
w.Header().Set("Content-Type", "application/json")
w.WriteHeader(status)
w.Write(js)
return nil
}
