new file mode 100644
--- /dev/null
+++ b/src/http/modules/ngx_http_charset_filter_module.c
@@ -0,0 +1,615 @@
+
+/*
+ * Copyright (C) Igor Sysoev
+ */
+
+
+#include <ngx_config.h>
+#include <ngx_core.h>
+#include <ngx_http.h>
+
+
+typedef struct {
+    char       **tables;
+    ngx_str_t    name;
+    ngx_uint_t   server;  /* unsigned     server:1; */
+} ngx_http_charset_t;
+
+
+typedef struct {
+    ngx_int_t   src;
+    ngx_int_t   dst;
+    char       *src2dst;
+    char       *dst2src;
+} ngx_http_charset_tables_t;
+
+
+typedef struct {
+    ngx_array_t  charsets;               /* ngx_http_charset_t */
+    ngx_array_t  tables;                 /* ngx_http_charset_tables_t */
+} ngx_http_charset_main_conf_t;
+
+
+typedef struct {
+    ngx_flag_t  enable;
+    ngx_flag_t  autodetect;
+
+    ngx_int_t   default_charset;
+    ngx_int_t   source_charset;
+} ngx_http_charset_loc_conf_t;
+
+
+typedef struct {
+    ngx_int_t   server;
+    ngx_int_t   client;
+} ngx_http_charset_ctx_t;
+
+
+static ngx_uint_t ngx_charset_recode(ngx_buf_t *b, char *table);
+
+static char *ngx_charset_map_block(ngx_conf_t *cf, ngx_command_t *cmd,
+    void *conf);
+static char *ngx_charset_map(ngx_conf_t *cf, ngx_command_t *dummy, void *conf);
+
+static char *ngx_http_set_charset_slot(ngx_conf_t *cf, ngx_command_t *cmd,
+    void *conf);
+static ngx_int_t ngx_http_add_charset(ngx_array_t *charsets, ngx_str_t *name);
+
+static ngx_int_t ngx_http_charset_filter_init(ngx_cycle_t *cycle);
+
+static void *ngx_http_charset_create_main_conf(ngx_conf_t *cf);
+static char *ngx_http_charset_init_main_conf(ngx_conf_t *cf, void *conf);
+static void *ngx_http_charset_create_loc_conf(ngx_conf_t *cf);
+static char *ngx_http_charset_merge_loc_conf(ngx_conf_t *cf,
+    void *parent, void *child);
+
+
+static ngx_command_t  ngx_http_charset_filter_commands[] = {
+
+    { ngx_string("charset_map"),
+      NGX_HTTP_MAIN_CONF|NGX_CONF_BLOCK|NGX_CONF_TAKE2,
+      ngx_charset_map_block,
+      NGX_HTTP_MAIN_CONF_OFFSET,
+      0,
+      NULL },
+
+    { ngx_string("default_charset"),
+      NGX_HTTP_MAIN_CONF|NGX_HTTP_SRV_CONF|NGX_HTTP_LOC_CONF|NGX_CONF_TAKE1,
+      ngx_http_set_charset_slot,
+      NGX_HTTP_LOC_CONF_OFFSET,
+      offsetof(ngx_http_charset_loc_conf_t, default_charset),
+      NULL },
+
+    { ngx_string("source_charset"),
+      NGX_HTTP_MAIN_CONF|NGX_HTTP_SRV_CONF|NGX_HTTP_LOC_CONF|NGX_CONF_TAKE1,
+      ngx_http_set_charset_slot,
+      NGX_HTTP_LOC_CONF_OFFSET,
+      offsetof(ngx_http_charset_loc_conf_t, source_charset),
+      NULL },
+
+    { ngx_string("charset"),
+      NGX_HTTP_MAIN_CONF|NGX_HTTP_SRV_CONF|NGX_HTTP_LOC_CONF|NGX_CONF_FLAG,
+      ngx_conf_set_flag_slot,
+      NGX_HTTP_LOC_CONF_OFFSET,
+      offsetof(ngx_http_charset_loc_conf_t, enable),
+      NULL },
+
+    { ngx_string("autodetect_charset"),
+      NGX_HTTP_MAIN_CONF|NGX_HTTP_SRV_CONF|NGX_HTTP_LOC_CONF|NGX_CONF_FLAG,
+      ngx_conf_set_flag_slot,
+      NGX_HTTP_LOC_CONF_OFFSET,
+      offsetof(ngx_http_charset_loc_conf_t, autodetect),
+      NULL },
+
+      ngx_null_command
+};
+
+
+static ngx_http_module_t  ngx_http_charset_filter_module_ctx = {
+    NULL,                                  /* pre conf */
+
+    ngx_http_charset_create_main_conf,     /* create main configuration */
+    ngx_http_charset_init_main_conf,       /* init main configuration */
+
+    NULL,                                  /* create server configuration */
+    NULL,                                  /* merge server configuration */
+
+    ngx_http_charset_create_loc_conf,      /* create location configuration */
+    ngx_http_charset_merge_loc_conf        /* merge location configuration */
+};
+
+
+ngx_module_t  ngx_http_charset_filter_module = {
+    NGX_MODULE,
+    &ngx_http_charset_filter_module_ctx,   /* module context */
+    ngx_http_charset_filter_commands,      /* module directives */
+    NGX_HTTP_MODULE,                       /* module type */
+    ngx_http_charset_filter_init,          /* init module */
+    NULL                                   /* init process */
+};
+
+
+static ngx_http_output_header_filter_pt  ngx_http_next_header_filter;
+static ngx_http_output_body_filter_pt    ngx_http_next_body_filter;
+
+
+static ngx_int_t
+ngx_http_charset_header_filter(ngx_http_request_t *r)
+{
+    ngx_http_charset_t            *charsets;
+    ngx_http_charset_ctx_t        *ctx;
+    ngx_http_charset_loc_conf_t   *lcf;
+    ngx_http_charset_main_conf_t  *mcf;
+
+    mcf = ngx_http_get_module_main_conf(r, ngx_http_charset_filter_module);
+    lcf = ngx_http_get_module_loc_conf(r, ngx_http_charset_filter_module);
+
+    if (lcf->enable == 0) {
+        return ngx_http_next_header_filter(r);
+    }
+
+    if (r->headers_out.content_type == NULL) {
+        return ngx_http_next_header_filter(r);
+    }
+
+    if (ngx_strncasecmp(r->headers_out.content_type->value.data,
+                                                              "text/", 5) != 0
+        && ngx_strncasecmp(r->headers_out.content_type->value.data,
+                                          "application/x-javascript", 24) != 0)
+    {
+        return ngx_http_next_header_filter(r);
+    }
+
+    if (ngx_strstr(r->headers_out.content_type->value.data, "charset") != NULL)
+    {
+        return ngx_http_next_header_filter(r);
+    }
+
+    if (r->headers_out.status == NGX_HTTP_MOVED_PERMANENTLY
+        || r->headers_out.status == NGX_HTTP_MOVED_TEMPORARILY)
+    {
+        /*
+         * do not set charset for the redirect because NN 4.x uses this
+         * charset instead of the next page charset
+         */
+
+        r->headers_out.charset.len = 0;
+        return ngx_http_next_header_filter(r);
+    }
+
+    if (r->headers_out.charset.len) {
+        return ngx_http_next_header_filter(r);
+    }
+
+    charsets = mcf->charsets.elts;
+    r->headers_out.charset = charsets[lcf->default_charset].name;
+
+    if (lcf->default_charset == lcf->source_charset) {
+        return ngx_http_next_header_filter(r);
+    }
+
+
+    ctx = ngx_pcalloc(r->pool, sizeof(ngx_http_charset_ctx_t));
+    if (ctx == NULL) {
+        return NGX_ERROR;
+    }
+
+    ngx_http_set_ctx(r, ctx, ngx_http_charset_filter_module);
+
+
+    r->filter_need_in_memory = 1;
+
+    return ngx_http_next_header_filter(r);
+}
+
+
+static ngx_int_t
+ngx_http_charset_body_filter(ngx_http_request_t *r, ngx_chain_t *in)
+{
+    char                          *table;
+    ngx_chain_t                   *cl;
+    ngx_http_charset_t            *charsets;
+    ngx_http_charset_ctx_t        *ctx;
+    ngx_http_charset_loc_conf_t   *lcf;
+    ngx_http_charset_main_conf_t  *mcf;
+
+    ctx = ngx_http_get_module_ctx(r, ngx_http_charset_filter_module);
+
+    if (ctx == NULL) {
+        return ngx_http_next_body_filter(r, in);
+    }
+
+    mcf = ngx_http_get_module_main_conf(r, ngx_http_charset_filter_module);
+    lcf = ngx_http_get_module_loc_conf(r, ngx_http_charset_filter_module);
+
+    charsets = mcf->charsets.elts;
+    table = charsets[lcf->source_charset].tables[lcf->default_charset];
+
+    for (cl = in; cl; cl = cl->next) {
+        ngx_charset_recode(cl->buf, table);
+    }
+
+    return ngx_http_next_body_filter(r, in);
+}
+
+
+static ngx_uint_t
+ngx_charset_recode(ngx_buf_t *b, char *table)
+{
+    u_char      *p;
+    ngx_uint_t   change;
+
+    change = 0;
+
+    for (p = b->pos; p < b->last; p++) {
+        if (*p != table[*p]) {
+            change = 1;
+            break;
+        }
+    }
+
+    if (change) {
+
+        while (p < b->last) {
+            *p = table[*p];
+            p++;
+        }
+
+        b->in_file = 0;
+    }
+
+    return change;
+}
+
+
+static char *
+ngx_charset_map_block(ngx_conf_t *cf, ngx_command_t *cmd, void *conf)
+{
+    ngx_http_charset_main_conf_t  *mcf = conf;
+
+    char                       *rv;
+    ngx_int_t                   src, dst;
+    ngx_uint_t                  i;
+    ngx_str_t                  *value;
+    ngx_conf_t                  pvcf;
+    ngx_http_charset_tables_t  *table;
+
+    value = cf->args->elts;
+
+    src = ngx_http_add_charset(&mcf->charsets, &value[1]);
+    if (src == NGX_ERROR) {
+        return NGX_CONF_ERROR;
+    }
+
+    dst = ngx_http_add_charset(&mcf->charsets, &value[2]);
+    if (dst == NGX_ERROR) {
+        return NGX_CONF_ERROR;
+    }
+
+    if (src == dst) {
+        ngx_conf_log_error(NGX_LOG_EMERG, cf, 0,
+                           "\"charset_map\" between the same charsets "
+                           "\"%V\" and \"%V\"", &value[1], &value[2]);
+        return NGX_CONF_ERROR;
+    }
+
+    table = mcf->tables.elts;
+    for (i = 0; i < mcf->tables.nelts; i++) {
+        if ((src == table->src && dst == table->dst)
+             || (src == table->dst && dst == table->src))
+        {
+            ngx_conf_log_error(NGX_LOG_EMERG, cf, 0,
+                               "duplicate \"charset_map\" between "
+                               "\"%V\" and \"%V\"", &value[1], &value[2]);
+            return NGX_CONF_ERROR;
+        }
+    }
+
+    table = ngx_array_push(&mcf->tables);
+    if (table == NULL) {
+        return NGX_CONF_ERROR;
+    }
+
+    table->src = src;
+    table->dst = dst;
+
+    table->src2dst = ngx_palloc(cf->pool, 256);
+    if (table->src2dst == NULL) {
+        return NGX_CONF_ERROR;
+    }
+
+    table->dst2src = ngx_palloc(cf->pool, 256);
+    if (table->dst2src == NULL) {
+        return NGX_CONF_ERROR;
+    }
+
+    for (i = 0; i < 128; i++) {
+        table->src2dst[i] = (char) i;
+        table->dst2src[i] = (char) i;
+    }
+
+    for (/* void */; i < 256; i++) {
+        table->src2dst[i] = '?';
+        table->dst2src[i] = '?';
+    }
+
+    pvcf = *cf;
+    cf->ctx = table;
+    cf->handler = ngx_charset_map;
+    cf->handler_conf = conf;
+
+    rv = ngx_conf_parse(cf, NULL);
+
+    *cf = pvcf;
+
+    return rv;
+}
+
+
+static char *
+ngx_charset_map(ngx_conf_t *cf, ngx_command_t *dummy, void *conf)
+{
+    ngx_int_t                   src, dst;
+    ngx_str_t                  *value;
+    ngx_http_charset_tables_t  *table;
+
+    if (cf->args->nelts != 2) {
+        ngx_conf_log_error(NGX_LOG_EMERG, cf, 0, "invalid parameters number");
+        return NGX_CONF_ERROR;
+    }
+
+    value = cf->args->elts;
+
+    src = ngx_hextoi(value[0].data, value[0].len);
+    if (src == NGX_ERROR || src > 255) {
+        ngx_conf_log_error(NGX_LOG_EMERG, cf, 0,
+                           "invalid value \"%V\"", &value[0]);
+        return NGX_CONF_ERROR;
+    }
+
+    dst = ngx_hextoi(value[1].data, value[1].len);
+    if (dst == NGX_ERROR || dst > 255) {
+        ngx_conf_log_error(NGX_LOG_EMERG, cf, 0,
+                           "invalid value \"%V\"", &value[1]);
+        return NGX_CONF_ERROR;
+    }
+
+    table = cf->ctx;
+
+    table->src2dst[src] = (char) dst;
+    table->dst2src[dst] = (char) src;
+
+    return NGX_CONF_OK;
+}
+
+
+static char *
+ngx_http_set_charset_slot(ngx_conf_t *cf, ngx_command_t *cmd, void *conf)
+{
+    char  *p = conf;
+
+    ngx_int_t                     *cp;
+    ngx_str_t                     *value;
+    ngx_http_charset_t            *charset;
+    ngx_http_charset_main_conf_t  *mcf;
+
+    cp = (ngx_int_t *) (p + cmd->offset);
+
+    if (*cp != NGX_CONF_UNSET) {
+        return "is duplicate";
+    }
+
+    mcf = ngx_http_conf_get_module_main_conf(cf,
+                                             ngx_http_charset_filter_module);
+
+    value = cf->args->elts;
+
+    *cp = ngx_http_add_charset(&mcf->charsets, &value[1]);
+    if (*cp == NGX_ERROR) {
+        return NGX_CONF_ERROR;
+    }
+
+    if (cmd->offset == offsetof(ngx_http_charset_loc_conf_t, source_charset)) {
+        charset = mcf->charsets.elts;
+        charset[*cp].server = 1;
+    }
+
+    return NGX_CONF_OK;
+}
+
+
+static ngx_int_t
+ngx_http_add_charset(ngx_array_t *charsets, ngx_str_t *name)
+{
+    ngx_uint_t           i;
+    ngx_http_charset_t  *c;
+
+    c = charsets->elts;
+    for (i = 0; i < charsets->nelts; i++) {
+        if (name->len != c[i].name.len) {
+            continue;
+        }
+
+        if (ngx_strcasecmp(name->data, c[i].name.data) == 0) {
+            break;
+        }
+    }
+
+    if (i < charsets->nelts) {
+        return i;
+    }
+
+    c = ngx_array_push(charsets);
+    if (c == NULL) {
+        return NGX_ERROR;
+    }
+
+    c->tables = NULL;
+    c->name = *name;
+    c->server = 0;
+
+    return i;
+}
+
+
+static ngx_int_t
+ngx_http_charset_filter_init(ngx_cycle_t *cycle)
+{
+    ngx_http_next_header_filter = ngx_http_top_header_filter;
+    ngx_http_top_header_filter = ngx_http_charset_header_filter;
+
+    ngx_http_next_body_filter = ngx_http_top_body_filter;
+    ngx_http_top_body_filter = ngx_http_charset_body_filter;
+
+    return NGX_OK;
+}
+
+
+static void *
+ngx_http_charset_create_main_conf(ngx_conf_t *cf)
+{
+    ngx_http_charset_main_conf_t  *mcf;
+
+    mcf = ngx_pcalloc(cf->pool, sizeof(ngx_http_charset_main_conf_t));
+    if (mcf == NULL) {
+        return NGX_CONF_ERROR;
+    }
+
+    if (ngx_array_init(&mcf->charsets, cf->pool, 2, sizeof(ngx_http_charset_t))
+                                                                  == NGX_ERROR)
+    {
+        return NGX_CONF_ERROR;
+    }
+
+    if (ngx_array_init(&mcf->tables, cf->pool, 4,
+                       sizeof(ngx_http_charset_tables_t)) == NGX_ERROR)
+    {
+        return NGX_CONF_ERROR;
+    }
+
+    return mcf;
+}
+
+
+static char *
+ngx_http_charset_init_main_conf(ngx_conf_t *cf, void *conf)
+{
+    ngx_http_charset_main_conf_t *mcf = conf;
+
+    ngx_uint_t                  i, n;
+    ngx_http_charset_t         *charset;
+    ngx_http_charset_tables_t  *tables;
+
+    tables = mcf->tables.elts;
+    charset = mcf->charsets.elts;
+
+    for (i = 0; i < mcf->charsets.nelts; i++) {
+        if (!charset[i].server) {
+            continue;
+        }
+
+        charset[i].tables = ngx_pcalloc(cf->pool,
+                                        sizeof(char *) * mcf->charsets.nelts);
+        if (charset[i].tables == NULL) {
+            return NGX_CONF_ERROR;
+        }
+
+        for (n = 0; n < mcf->tables.nelts; n++) {
+            if ((ngx_int_t) i == tables[n].src) {
+                charset[i].tables[tables[n].dst] = tables[n].src2dst;
+                continue;
+            }
+
+            if ((ngx_int_t) i == tables[n].dst) {
+                charset[i].tables[tables[n].src] = tables[n].dst2src;
+            }
+        }
+    }
+
+    for (i = 0; i < mcf->charsets.nelts; i++) {
+        if (!charset[i].server) {
+            continue;
+        }
+
+        for (n = 0; n < mcf->charsets.nelts; n++) {
+            if (i == n) {
+                continue;
+            }
+
+            if (charset[i].tables[n]) {
+                continue;
+            }
+
+            ngx_log_error(NGX_LOG_EMERG, cf->log, 0,
+                          " no \"charset_map\" between the charsets "
+                          "\"%V\" and \"%V\"",
+                          &charset[i].name, &charset[n].name);
+            return NGX_CONF_ERROR;
+        }
+    }
+
+    return NGX_CONF_OK;
+}
+
+
+static void *
+ngx_http_charset_create_loc_conf(ngx_conf_t *cf)
+{
+    ngx_http_charset_loc_conf_t  *lcf;
+
+    lcf = ngx_pcalloc(cf->pool, sizeof(ngx_http_charset_loc_conf_t));
+    if (lcf == NULL) {
+        return NGX_CONF_ERROR;
+    }
+
+    lcf->enable = NGX_CONF_UNSET;
+    lcf->autodetect = NGX_CONF_UNSET;
+    lcf->default_charset = NGX_CONF_UNSET;
+    lcf->source_charset = NGX_CONF_UNSET;
+
+    return lcf;
+}
+
+
+static char *
+ngx_http_charset_merge_loc_conf(ngx_conf_t *cf, void *parent, void *child)
+{
+    ngx_http_charset_loc_conf_t *prev = parent;
+    ngx_http_charset_loc_conf_t *conf = child;
+
+    ngx_conf_merge_value(conf->enable, prev->enable, 0);
+    ngx_conf_merge_value(conf->autodetect, prev->autodetect, 0);
+
+
+    if (conf->default_charset == NGX_CONF_UNSET) {
+        conf->default_charset = prev->default_charset;
+    }
+
+    if (conf->source_charset == NGX_CONF_UNSET) {
+        conf->source_charset = prev->source_charset;
+    }
+
+    if (conf->default_charset == NGX_CONF_UNSET
+        && conf->source_charset != NGX_CONF_UNSET)
+    {
+        conf->default_charset = conf->source_charset;
+    }
+
+    if (conf->source_charset == NGX_CONF_UNSET
+        && conf->default_charset != NGX_CONF_UNSET)
+    {
+        conf->source_charset = conf->default_charset;
+    }
+
+    if (conf->enable
+        && (conf->default_charset == NGX_CONF_UNSET
+            || conf->source_charset == NGX_CONF_UNSET))
+    {
+        ngx_conf_log_error(NGX_LOG_EMERG, cf, 0,
+                           "the \"source_charset\" or \"default_charset\" "
+                           "must be specified when \"charset\" is on");
+        return NGX_CONF_ERROR;
+    }
+
+    return NGX_CONF_OK;
+}