php 使用SplFileObject读取CSV文件。从CSV文件定义标题或管理标题行。返回数组中的行，标题值为

Posted 2021-05-05

<?php

/**
 * Class CsvReader
 *
 * Reading CSV file with SplFileObject.
 * Define a header or manage the header line from CSV file.
 * Returns rows in arrays with header values as array keys.
 *
 * If a header is defined then for each row we will check that
 * the number of columns corresponds to the number of header elements.
 * If this does not match then the line is considered invalid.
 * An invalid line in a CSV file will be returned as an array
 * comprising a single null field unless using skipInvalid.
 *
 * Use the safeMode so that the reader still returns invalid lines.
 */
class CsvReader implements \Iterator, \Countable
{

    /**
     * @var array;
     */
    private $data;

    /**
     * @var bool
     */
    private $hasHeader = false;

    /**
     * @var array
     */
    private $header = [];

    /**
     * @var int
     */
    private $countHeader = 0;

    /**
     * @var string
     */
    private $filename;

    /**
     * @var \SplFileObject
     */
    private $file;

    /**
     * @var int
     */
    private $count = -1;

    /**
     * @var array
     */
    private $invalids = [];

    /**
     * @var bool
     */
    private $skipInvalid = false;

    /**
     * @var bool
     */
    private $safeMode = false;


    /**
     * CsvReader constructor.
     * @param $filename
     * @param string $delimiter
     * @param string $enclosure
     * @param string $escape
     */
    public function __construct($filename, $delimiter=',', $enclosure='"', $escape='\\')
    {
        $this->filename = $filename;

        $this->file = new \SplFileObject($this->filename, 'r');
        $this->file->setFlags(
            \SplFileObject::READ_CSV
            | \SplFileObject::READ_AHEAD
            | \SplFileObject::SKIP_EMPTY
            | \SplFileObject::DROP_NEW_LINE
        );

        $this->file->setCsvControl($delimiter, $enclosure, $escape);
    }

    /**
     * {@inheritdoc}
     */
    public function __destruct()
    {
        unset($this->file);
    }


    /**
     * @throws \Exception
     */
    private function computeHeader()
    {
        if ($this->countHeader === 0 && $this->hasHeader === true) {
            $currentPosition = $this->file->key();

            $this->file->seek(0);
            $this->header = $this->file->current();

            $this->file->seek($currentPosition);
        }

        if ($this->countHeader === 0 && count($this->header) > 0) {
            $header = array_unique(array_filter($this->header, 'is_string'));
            if ($this->header !== $header) {
                throw new \Exception('The header must be empty or a flat array with unique string values');
            }

            $this->header = $header;
            $this->countHeader = count($this->header);
        }
    }

    /**
     * Convert current line to array with header values as array keys
     */
    private function buildData()
    {
        if ($this->file->valid() === false) {
            return;
        }

        $this->data = [];
        $line = $this->combineHeader();
        $this->data = $line;
    }

    /**
     * @return array
     */
    private function combineHeader()
    {
        $this->computeHeader();

        if ($this->hasHeader === true && $this->file->key() === 0) {
            $this->file->next();
        }

        $line = $this->file->current();

        if ($this->safeMode === false) {
            try {
                $this->ensureIsValid($line);
            } catch (\LogicException $e) {
                $this->invalids[$this->key()] = $e->getMessage();

                if ($this->skipInvalid === true) {
                    $this->file->next();
                    $this->buildData();
                }

                return [null];
            }
        }

        if ($this->countHeader > 0) {
            $line = array_slice(array_pad($line, $this->countHeader, null), 0, $this->countHeader);
            //fill header keys
            $line = array_combine($this->header, $line);
        }

        return $line;
    }
    /**
     * Returns true if the file contains at least one invalid line. False otherwise.
     *
     * @return bool
     */
    public function check()
    {
        $this->read();
        return (bool)count($this->invalids) > 0;
    }

    /**
     * @param $line
     */
    private function ensureIsValid($line)
    {
        if ($this->countHeader > 0) {
            $countColumn = count($line);

            if ($this->countHeader !== $countColumn) {
                throw new \LogicException(
                    sprintf(
                        'header has %d elements. Found %d columns on line %d.',
                        $this->countHeader,
                        $countColumn,
                        $this->file->key()
                    )
                );
            }
        }
    }

    /**
     * Read the entire file
     *
     * @return array
     */
    public function read()
    {
        $rows = [];
        $this->file->rewind();
        while ($this->file->eof() === false) {
            $this->file->next();
            $this->buildData();
            $rows[] = $this->data;
        }
        $this->file->rewind();

        return $rows;
    }

    /**
     * @return int
     */
    public function count()
    {
        if (-1 === $this->count) {
            $this->rewind();
            $count = iterator_count($this->file);

            if ($count > 0 && $this->hasHeader === true) {
                $count--;
            }
            $this->count = $count;
            $this->rewind();
        }
        return $this->count;
    }

    /**
     * Return the first row
     *
     * @return array
     */
    public function first()
    {
        return $this->rewind()->current();
    }

    /**
     * Move to specified line
     *
     * @param int $position
     * @return $this
     */
    public function move($position)
    {
        $this->file->seek($position);
        return $this;
    }

    /**
     * Rewind iterator to the first element
     */
    public function rewind()
    {
        if ($this->file) {
            $this->file->rewind();
        }

        $this->buildData();
        return $this;
    }

    /**
     * Return the current row
     *
     * @return array
     */
    public function current()
    {
        $this->buildData();
        return $this->data;
    }

    /**
     * Return the key of the current row
     *
     * @return int
     */
    public function key()
    {
        return $this->file->key();
    }

    /**
     * Return the next row
     *
     * @return array
     */
    public function next()
    {
        $this->file->next();
        $this->buildData();
        return $this->data;
    }

    /**
     * Check if current position is valid
     *
     * @return bool
     */
    public function valid()
    {
        return $this->file->valid();
    }

    /**
     * @param bool $hasHeader
     * @return CsvReader
     */
    public function setHasHeader($hasHeader)
    {
        $this->hasHeader = $hasHeader;
        return $this;
    }

    /**
     * @param array $header
     * @return CsvReader
     */
    public function setHeader(array $header)
    {
        $this->header = $header;
        return $this;
    }

    /**
     * @param bool $skipInvalid
     * @return CsvReader
     */
    public function setSkipInvalid($skipInvalid)
    {
        $this->skipInvalid = $skipInvalid;
        return $this;
    }

    /**
     * @param bool $safeMode
     * @return CsvReader
     */
    public function setSafeMode($safeMode)
    {
        $this->safeMode = $safeMode;
        return $this;
    }


    /**
     * @return array
     */
    public function getInvalids()
    {
        return $this->invalids;
    }

    /**
     * @return array
     */
    public function getHeader()
    {
        return $this->header;
    }
}