How can I capture the result of var dump to a string

Question

I d like to capture the output of var dump to a string   The PHP documentation says      As with anything that outputs its result directly to the browser  the output-control functions can be used to capture the output of this function  and save it in a string  for example     What would be an example of how that might work   print r   isn t a valid possibility  because it s not going to give me the information that I need

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If you want to have a look at a variable s contents during runtime  consider using a real debugger like XDebug  That way you don t need to mess up your source code  and you can use a debugger even while normal users visit your application  They won t notice

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From http   htmlexplorer com 2015 01 assign-output-var dump-print r-php-variable html      var dump and print r functions can only output directly to browser  So the output of these functions can only retrieved by using output control functions of php  Below method may be useful to save the output   function assignVarDumpValueToString  object        ob start        var dump  object        result   ob get clean        return  result       ob get clean   can only clear last data entered to internal buffer  So ob get contents method will be useful if you have multiple entries   From the same source as above    function varDumpToErrorLog   var null        ob start                          start reading the internal buffer     var dump   var                  grabbed information   ob get contents       assigning the internal buffer contents to variable     ob end clean                      clearing the internal buffer      error log   grabbed information             saving the information to error log

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You could also do this    dump   print r  variable  true

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This maybe a bit off topic   I was looking for a way to write this kind of information to the Docker log of my PHP-FPM container and came up with the snippet below  I m sure this can be used by Docker PHP-FPM users   fwrite fopen  php   stdout    w    var export  object  true

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From the PHP manual      This function displays structured information about one or more expressions that includes its type and value    So  here is the real return version of PHP s var dump    which actually accepts a variable-length argument list   function var dump str          argc   func num args         argv   func get args         if   argc  gt  0            ob start            call user func array  var dump    argv            result   ob get contents            ob end clean            return  result             return

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function return var dump           It works like var dump  but it returns a string instead of printing it       args   func get args       For  lt 5 3 0 support         ob start        call user func array  var dump    args       return ob get clean

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I really like var dump   s verbose output and wasn t satisfied with var export   s or print r   s output because it didn t give as much information  e g  data type missing  length missing    To write secure and predictable code  sometimes it s useful to differentiate between an empty string and a null  Or between a 1 and a true  Or between a null and a false  So I want my data type in the output    Although helpful  I didn t find a clean and simple solution in the existing responses to convert the colored output of var dump   to a human-readable output into a string without the html tags and including all the details from var dump      Note that if you have a colored var dump    it means that you have Xdebug installed which overrides php s default var dump   to add html colors   For that reason  I created this slight variation giving exactly what I need    function dbg var dump  var                ob start            var dump  var            result   ob get clean            return strip tags strtr  result      amp gt     gt     gt               Returns the below nice string   array  size 6     functioncall    gt  string  add-time-property   length 17     listingid    gt  string  57   length 2     weekday    gt  string  0   length 1     starttime    gt  string  00 00   length 5     endtime    gt  string  00 00   length 5     price    gt  string     length 0    Hope it helps someone

User · Answer

Try var export  You may want to check out var export     while it doesn t provide the same output as var dump it does provide a second  return parameter which will cause it to return its output rather than print it    debug   var export  my var  true     Why   I prefer this one-liner to using ob start and ob get clean     I also find that the output is a little easier to read  since it s just PHP code   The difference between var dump and var export is that var export returns a  parsable string representation of a variable  while var dump simply dumps information about a variable   What this means in practice is that var export gives you valid PHP code  but may not give you quite as much information about the variable  especially if you re working with resources    Demo    demo   array       bool    gt  false       int    gt  1       float    gt  3 14       string    gt   hello world        array    gt  array         object    gt  new stdClass         resource    gt  tmpfile         null    gt  null         var export -- nice  one-liner  debug export   var export  demo  true       var dump ob start    var dump  demo    debug dump   ob get clean        print r -- included for completeness  though not recommended  debug printr   print r  demo  true     The difference in output   var export   debug export in above example     array      bool    gt  false     int    gt  1     float    gt  3 1400000000000001     string    gt   hello world      array    gt     array           object    gt     stdClass    set state array           resource    gt  NULL     Note that this resource pointer is now NULL    null    gt  NULL      var dump   debug dump in above example     array 8        bool    gt    bool false      int    gt    int 1      float    gt    float 3 14      string    gt    string 11   hello world      array    gt    array 0            object    gt    object stdClass  1  0            resource    gt    resource 4  of type  stream      null    gt    NULL     print r   debug printr in above example    Array        bool    gt        int    gt  1      float    gt  3 14      string    gt  hello world      array    gt  Array                           object    gt  stdClass Object                           resource    gt  Resource id  4      null    gt       Caveat  var export does not handle circular references  If you re trying to dump a variable with circular references  calling var export will result in a PHP warning     circular   array      circular  self     amp   circular   var export  circular     Results in     Warning  var export does not handle circular references in example php on line 3  array       self    gt      array         self    gt  NULL             Both var dump and print r  on the other hand  will output the string  RECURSION  when encountering circular references

User · Answer

Long string  Just use echo  var   instead of dump  var     Object or Array  var dump   lt pre gt   json encode  var    lt  pre gt

User · Answer

You may also try to use the serialize   function  Sometimes it is very useful for debugging purposes

User · Answer

Use output buffering    lt  php ob start    var dump  someVar    result   ob get clean      gt

User · Answer

Here is the complete solution as a function   function varDumpToString   var        ob start        var dump  var       return ob get clean

User · Answer

Also echo json encode  dataobject   might be helpful

[php] How can I capture the result of var_dump to a string?

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