php 57 lines · 8 steps

Validating a CSV import in Laravel

A row-by-row CSV importer that accumulates per-line validation errors and only persists clean records.

Explained by highlit
Laravel Intermediate csv-parsing validation error-accumulation data-import
1public function importCustomers(UploadedFile $file): array
2{
3 $errors = [];
4 $imported = 0;
5 
6 $handle = fopen($file->getRealPath(), 'r');
7 $header = fgetcsv($handle);
8 
9 if ($header !== ['name', 'email', 'age', 'country']) {
10 fclose($handle);
11 return ['errors' => ['Invalid CSV header. Expected: name, email, age, country'], 'imported' => 0];
12 }
13 
14 $line = 1;
15 while (($row = fgetcsv($handle)) !== false) {
16 $line++;
17 
18 if (count($row) !== 4) {
19 $errors[] = "Line {$line}: expected 4 columns, got " . count($row) . '.';
20 continue;
21 }
22 
23 [$name, $email, $age, $country] = array_map('trim', $row);
24 
25 if ($name === '') {
26 $errors[] = "Line {$line}: name is required.";
27 }
28 
29 if (!filter_var($email, FILTER_VALIDATE_EMAIL)) {
30 $errors[] = "Line {$line}: '{$email}' is not a valid email.";
31 } elseif (Customer::where('email', $email)->exists()) {
32 $errors[] = "Line {$line}: email '{$email}' already exists.";
33 }
34 
35 if (!ctype_digit($age) || (int) $age < 18) {
36 $errors[] = "Line {$line}: age must be a whole number of at least 18.";
37 }
38 
39 if (!in_array(strtoupper($country), self::ALLOWED_COUNTRIES, true)) {
40 $errors[] = "Line {$line}: unsupported country code '{$country}'.";
41 }
42 
43 if (empty(array_filter($errors, fn ($e) => str_starts_with($e, "Line {$line}:")))) {
44 Customer::create([
45 'name' => $name,
46 'email' => $email,
47 'age' => (int) $age,
48 'country' => strtoupper($country),
49 ]);
50 $imported++;
51 }
52 }
53 
54 fclose($handle);
55 
56 return ['errors' => $errors, 'imported' => $imported];
57}
01 / 01
STEP 01

Walkthrough

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Three takeaways
  1. 1Accumulating errors instead of failing fast lets you report every problem in one pass.
  2. 2Validating the header up front avoids wasting work on a fundamentally malformed file.
  3. 3Tagging errors by line number lets you decide per-row whether a record is safe to persist.

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